From 6d72168ca40b9d1873d4a51421596cb0f78b2404 Mon Sep 17 00:00:00 2001
From: Markus Gans <guru@server.home.net>
Date: Tue, 11 Aug 2020 23:04:46 +0200
Subject: [PATCH] New callback backend was implemented

---
 ChangeLog                        |   4 +
 doc/class_template.h             |   1 -
 doc/first-steps.md               |  82 ++---
 doc/user-theme.md                |  10 +-
 examples/7segment.cpp            |  11 +-
 examples/background-color.cpp    |  16 +-
 examples/busy.cpp                |  13 +-
 examples/calculator.cpp          |  25 +-
 examples/checklist.cpp           |   6 +-
 examples/choice.cpp              |   9 +-
 examples/dialog.cpp              |   7 +-
 examples/fullwidth-character.cpp |  14 +-
 examples/input-dialog.cpp        |  30 +-
 examples/listbox.cpp             |   4 +-
 examples/listview.cpp            |  10 +-
 examples/menu.cpp                |  12 +-
 examples/mouse.cpp               |   6 +-
 examples/scrollview.cpp          |  28 +-
 examples/term-attributes.cpp     |  12 +-
 examples/treeview.cpp            |   4 +-
 examples/ui.cpp                  | 185 +++++------
 examples/watch.cpp               |  16 +-
 examples/windows.cpp             |  72 +++--
 src/Makefile.am                  |   2 +
 src/Makefile.clang               |   2 +
 src/Makefile.gcc                 |   2 +
 src/fbuttongroup.cpp             |   8 +-
 src/fcallback.cpp                |  42 +++
 src/fcombobox.cpp                |  16 +-
 src/fdialog.cpp                  |  15 +-
 src/ffiledialog.cpp              |  24 +-
 src/flabel.cpp                   |   8 +-
 src/fmenu.cpp                    |  17 +-
 src/fmenubar.cpp                 |  14 +-
 src/fmenuitem.cpp                |  29 +-
 src/fmessagebox.cpp              |  17 +-
 src/fradiomenuitem.cpp           |   3 +-
 src/fspinbox.cpp                 |  15 +-
 src/fstatusbar.cpp               |  10 +-
 src/fvterm.cpp                   |   4 +-
 src/fwidget.cpp                  | 101 +-----
 src/fwidget_functions.cpp        |   7 +
 src/include/final/fapplication.h |  13 +-
 src/include/final/fbuttongroup.h |   2 +-
 src/include/final/fcallback.h    | 449 ++++++++++++++++++++++++++
 src/include/final/fcombobox.h    |   8 +-
 src/include/final/fdialog.h      |   6 +-
 src/include/final/ffiledialog.h  |  12 +-
 src/include/final/flabel.h       |   2 +-
 src/include/final/fmenu.h        |   6 +-
 src/include/final/fmenubar.h     |   2 +-
 src/include/final/fmenuitem.h    |   4 +-
 src/include/final/fmessagebox.h  |   2 +-
 src/include/final/fscrollbar.h   |   2 +-
 src/include/final/fspinbox.h     |   4 +-
 src/include/final/fstatusbar.h   |   2 +-
 src/include/final/ftypes.h       |  41 +--
 src/include/final/fvterm.h       |   2 +-
 src/include/final/fwidget.h      | 161 +++-------
 test/Makefile.am                 |   2 +
 test/fcallback-test.cpp          | 534 +++++++++++++++++++++++++++++++
 61 files changed, 1524 insertions(+), 643 deletions(-)
 create mode 100644 src/fcallback.cpp
 create mode 100644 src/include/final/fcallback.h
 create mode 100644 test/fcallback-test.cpp

diff --git a/ChangeLog b/ChangeLog
index 35a3eed8..e5bfbfd5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2020-08-11  Markus Gans  <guru.mail@muenster.de>
+	* New callback backend was implemented. Callback functions with any 
+	  number of arguments are now possible.
+
 2020-07-19  Markus Gans  <guru.mail@muenster.de>
 	* API: Some method name changes: 
 	       FObject::delOwnTimer() -> FObject::delOwnTimers() 
diff --git a/doc/class_template.h b/doc/class_template.h
index c3cc4325..c8352d65 100644
--- a/doc/class_template.h
+++ b/doc/class_template.h
@@ -126,4 +126,3 @@ class FClassName
 
 #endif  // FCLASSNAME_H
 
-
diff --git a/doc/first-steps.md b/doc/first-steps.md
index e42e0b11..a52e48a0 100644
--- a/doc/first-steps.md
+++ b/doc/first-steps.md
@@ -609,10 +609,8 @@ use `delAllCallbacks()` to remove all existing callbacks from an object.
 
 using namespace finalcut;
 
-void cb_changeText (FWidget* w, FDataPtr data)
+void cb_changeText (const FButton& button, FLabel& label)
 {
-  FButton& button = *(static_cast<FButton*>(w));
-  FLabel& label = *(static_cast<FLabel*>(data));
   label.clear();
   label << "The " << button.getClassName() << " was pressed";
   label.redraw();
@@ -635,9 +633,10 @@ int main (int argc, char* argv[])
   // Connect the button signal "clicked" with the callback function
   button.addCallback
   (
-    "clicked",
-    F_FUNCTION_CALLBACK (&cb_changeText),
-    &label
+    "clicked",          // Callback signal
+    &cb_changeText,     // Function pointer
+    std::cref(button),  // First function argument
+    std::ref(label)     // Second function argument
   );
 
   FWidget::setMainWidget(&dialog);
@@ -683,11 +682,9 @@ int main (int argc, char* argv[])
   // Connect the button signal "clicked" with the lambda expression
   button.addCallback
   (
-    "clicked",
-    [] (FWidget* w, FDataPtr d)
+    "clicked",                          // Callback signal
+    [] (FButton& button, FDialog& dgl)  // Lambda function
     {
-      FButton& button = *(static_cast<FButton*>(w));
-
       if ( button.getY() != 2 )
       {
         button.setPos (FPoint{15, 2});
@@ -699,9 +696,10 @@ int main (int argc, char* argv[])
         button.setText("&bottom");
       }
 
-      static_cast<FDialog*>(d)->redraw();
+      dgl.redraw();
     },
-    &dialog
+    std::ref(button),                   // First function argument
+    std::ref(dialog)                    // Second function argument
   );
 
   FWidget::setMainWidget(&dialog);
@@ -748,9 +746,10 @@ class dialogWidget : public FDialog
       // Connect the button signal "clicked" with the callback method
       button.addCallback
       (
-        "clicked",
-        F_METHOD_CALLBACK (this, &FApplication::cb_exitApp),
-        nullptr
+        "clicked",                            // Callback signal
+        finalcut::getFApplication(),          // Class instance
+        &finalcut::FApplication::cb_exitApp,  // Method pointer
+        this                                  // Function argument
       );
     }
 
@@ -810,45 +809,22 @@ class dialogWidget : public FDialog
       label.setAlignment (fc::alignRight);
       label.setForegroundColor (fc::Black);
       plus.setGeometry (FPoint{3, 3}, size);
-      minus.setGeometry (FPoint{13, 3}, size);
+      minus.setGeometry (FPoint{3, 3} + FPoint{10, 0}, size);
       plus.setNoUnderline();
       minus.setNoUnderline();
 
       // Connect the button signal "clicked" with the callback method
-      plus.addCallback
-      (
-        "clicked",
-        F_METHOD_CALLBACK (this, &dialogWidget::cb_plus)
-      );
-
-      minus.addCallback
-      (
-        "clicked",
-        F_METHOD_CALLBACK (this, &dialogWidget::cb_minus)
-      );
+      plus.addCallback ("clicked", this, &dialogWidget::cb_plus);
+      minus.addCallback ("clicked", this, &dialogWidget::cb_minus);
 
       // Connect own signals
-      addCallback
-      (
-        "hot",
-        F_METHOD_CALLBACK (this, &dialogWidget::cb_set_red)
-      );
-
-      addCallback
-      (
-        "regular",
-        F_METHOD_CALLBACK (this, &dialogWidget::cb_set_black)
-      );
-
-      addCallback
-      (
-        "cold",
-        F_METHOD_CALLBACK (this, &dialogWidget::cb_set_blue)
-      );
+      addCallback ("hot", this, &dialogWidget::cb_set_red);
+      addCallback ("regular", this, &dialogWidget::cb_set_black);
+      addCallback ("cold", this, &dialogWidget::cb_set_blue);
     }
 
   private:
-    void cb_plus (FWidget*, FDataPtr)
+    void cb_plus()
     {
       if ( t < 100 )
         t++;
@@ -861,7 +837,7 @@ class dialogWidget : public FDialog
       setTemperature();
     }
 
-    void cb_minus (FWidget*, FDataPtr)
+    void cb_minus()
     {
       if ( t > -99 )
         t--;
@@ -874,17 +850,17 @@ class dialogWidget : public FDialog
       setTemperature();
     }
 
-    void cb_set_blue (FWidget*, FDataPtr)
+    void cb_set_blue()
     {
       label.setForegroundColor (fc::Blue);
     }
 
-    void cb_set_black (FWidget*, FDataPtr)
+    void cb_set_black()
     {
       label.setForegroundColor (fc::Black);
     }
 
-    void cb_set_red (FWidget*, FDataPtr)
+    void cb_set_red()
     {
       label.setForegroundColor (fc::Red);
     }
@@ -1291,8 +1267,7 @@ class dialogWidget : public FDialog
         btn->addCallback
         (
           "clicked",
-          F_METHOD_CALLBACK (this, &dialogWidget::cb_button),
-          static_cast<FDataPtr>(&std::get<2>(b))
+          this, &dialogWidget::cb_button, std::get<2>(b)
         );
       };
     }
@@ -1300,10 +1275,9 @@ class dialogWidget : public FDialog
   private:
     typedef std::tuple<FString, FPoint, FPoint, FColorPair> direction;
 
-    void cb_button (FWidget*, FDataPtr data)
+    void cb_button (const FPoint& p)
     {
-      FPoint* p = static_cast<FPoint*>(data);
-      scrollview.scrollTo(*p);
+      scrollview.scrollTo(p);
     }
 
     FScrollView scrollview{this};
diff --git a/doc/user-theme.md b/doc/user-theme.md
index 483b6a60..fc59dd45 100644
--- a/doc/user-theme.md
+++ b/doc/user-theme.md
@@ -370,7 +370,7 @@ class dialogWidget final : public FDialog
       Browse.addCallback
       (
         "clicked",
-        F_METHOD_CALLBACK (this, &dialogWidget::cb_FileBrowse)
+        this, &dialogWidget::cb_FileBrowse
       );
       Apply.setGeometry (FPoint{24, 5}, FSize{10, 1});
       Apply.setStatusbarMessage("Apply settings");
@@ -379,17 +379,19 @@ class dialogWidget final : public FDialog
       Quit.addCallback
       (
         "clicked",
-        F_METHOD_CALLBACK (this, &finalcut::FApplication::cb_exitApp)
+        finalcut::getFApplication(),
+        &finalcut::FApplication::cb_exitApp,
+        this  
       );
       Open.addCallback
       (
         "clicked",
-        F_METHOD_CALLBACK (this, &dialogWidget::cb_FileBrowse)
+        this, &dialogWidget::cb_FileBrowse
       );
     }
 
   private:
-    void cb_FileBrowse (finalcut::FWidget*, FDataPtr)
+    void cb_FileBrowse()
     {
       auto filename = FFileDialog::fileOpenChooser(this);
 
diff --git a/examples/7segment.cpp b/examples/7segment.cpp
index b46eee0d..89991113 100644
--- a/examples/7segment.cpp
+++ b/examples/7segment.cpp
@@ -100,18 +100,19 @@ SegmentView::SegmentView (finalcut::FWidget* parent)
   Input.addCallback
   (
     "changed",
-    [] (const finalcut::FWidget*, FDataPtr data)
+    [] (SegmentView& dialog)
     {
-      auto dialog = static_cast<SegmentView*>(data);
-      dialog->redraw();
+      dialog.redraw();
     },
-    this
+    std::ref(*this)
   );
 
   Exit.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &finalcut::FApplication::cb_exitApp)
+    finalcut::getFApplication(),
+    &finalcut::FApplication::cb_exitApp,
+    this
   );
 }
 
diff --git a/examples/background-color.cpp b/examples/background-color.cpp
index c44f0a95..3b0d16eb 100644
--- a/examples/background-color.cpp
+++ b/examples/background-color.cpp
@@ -58,8 +58,8 @@ class Background final : public finalcut::FDialog
 
   private:
     // Callback method
-    void cb_changed (const finalcut::FWidget*, const FDataPtr);
-    void cb_choice (const finalcut::FWidget*, const FDataPtr);
+    void cb_changed();
+    void cb_choice();
 
     // Data members
     finalcut::FComboBox color_choice{this};
@@ -148,7 +148,9 @@ Background::Background (finalcut::FWidget* parent)
   quit.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &finalcut::FApplication::cb_exitApp)
+    finalcut::getFApplication(),
+    &finalcut::FApplication::cb_exitApp,
+    this
   );
 
   for (const auto spinbox : {&red, &green, &blue})
@@ -156,7 +158,7 @@ Background::Background (finalcut::FWidget* parent)
     spinbox->addCallback
     (
       "changed",
-      F_METHOD_CALLBACK (this, &Background::cb_changed)
+      this, &Background::cb_changed
     );
   }
 
@@ -165,7 +167,7 @@ Background::Background (finalcut::FWidget* parent)
     color_choice.addCallback
     (
       signal,
-      F_METHOD_CALLBACK (this, &Background::cb_choice)
+      this, &Background::cb_choice
     );
   }
 }
@@ -175,7 +177,7 @@ Background::~Background()  // destructor
 { }
 
 //----------------------------------------------------------------------
-void Background::cb_changed (const finalcut::FWidget*, const FDataPtr)
+void Background::cb_changed()
 {
   if ( ! finalcut::FTerm::canChangeColorPalette() )
     return;
@@ -189,7 +191,7 @@ void Background::cb_changed (const finalcut::FWidget*, const FDataPtr)
 }
 
 //----------------------------------------------------------------------
-void Background::cb_choice (const finalcut::FWidget*, const FDataPtr)
+void Background::cb_choice()
 {
   if ( ! finalcut::FTerm::canChangeColorPalette() )
     return;
diff --git a/examples/busy.cpp b/examples/busy.cpp
index f867fd0f..24e3bf22 100644
--- a/examples/busy.cpp
+++ b/examples/busy.cpp
@@ -41,7 +41,7 @@ class Dialog final : public finalcut::FDialog
     void onTimer (finalcut::FTimerEvent*) override;
 
     // Callback method
-    void cb_start (const finalcut::FWidget*, const FDataPtr);
+    void cb_start();
 
     // Data members
     finalcut::FSpinBox seconds{this};
@@ -67,21 +67,22 @@ Dialog::Dialog (FWidget* parent)
   seconds.addCallback
   (
     "activate",
-    F_METHOD_CALLBACK (this, &Dialog::cb_start)
+    this, &Dialog::cb_start
   );
 
   start.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &Dialog::cb_start)
+    this, &Dialog::cb_start
   );
 
   quit.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &finalcut::FApplication::cb_exitApp)
+    finalcut::getFApplication(),
+    &finalcut::FApplication::cb_exitApp,
+    this
   );
-
 }
 
 //----------------------------------------------------------------------
@@ -105,7 +106,7 @@ void Dialog::onTimer (finalcut::FTimerEvent*)
 }
 
 //----------------------------------------------------------------------
-void Dialog::cb_start (const finalcut::FWidget*, const FDataPtr)
+void Dialog::cb_start()
 {
   if ( seconds.getValue() < 1 )
     return;
diff --git a/examples/calculator.cpp b/examples/calculator.cpp
index 1c9eb947..8160f41e 100644
--- a/examples/calculator.cpp
+++ b/examples/calculator.cpp
@@ -119,13 +119,6 @@ class Calc final : public finalcut::FDialog
     // Destructor
     ~Calc() override;
 
-    // Event handlers
-    void           onKeyPress (finalcut::FKeyEvent*) override;
-    void           onClose (finalcut::FCloseEvent*) override;
-
-    // Callback method
-    void           cb_buttonClicked (const finalcut::FWidget*, FDataPtr);
-
   private:
     // Typedef and Enumeration
     typedef std::function<void(lDouble&)> keyFunction;  // Member function
@@ -218,6 +211,13 @@ class Calc final : public finalcut::FDialog
     const wchar_t* getButtonText (const std::size_t) const;
     void           mapKeyFunctions();
 
+    // Event handlers
+    void           onKeyPress (finalcut::FKeyEvent*) override;
+    void           onClose (finalcut::FCloseEvent*) override;
+
+    // Callback method
+    void           cb_buttonClicked (Calc::button);
+
     // Data members
     bool              error{false};
     bool              arcus_mode{false};
@@ -230,7 +230,7 @@ class Calc final : public finalcut::FDialog
     char              infix_operator{'\0'};
     char              last_infix_operator{'\0'};
     finalcut::FString input{""};
-    std::size_t       button_no[Calc::NUM_OF_BUTTONS]{};
+    button            button_no[Calc::NUM_OF_BUTTONS]{};
 
     struct stack_data
     {
@@ -257,7 +257,7 @@ Calc::Calc (FWidget* parent)
   clearInfixOperator();
   std::setlocale(LC_NUMERIC, "C");
 
-  for (std::size_t key{0}; key < Calc::NUM_OF_BUTTONS; key++)
+  for (button key{Sine}; key < Calc::NUM_OF_BUTTONS; key = button(key + 1))
   {
     auto btn = std::make_shared<Button>(this);
     button_no[key] = key;
@@ -284,8 +284,8 @@ Calc::Calc (FWidget* parent)
     btn->addCallback
     (
       "clicked",
-      F_METHOD_CALLBACK (this, &Calc::cb_buttonClicked),
-      &button_no[key]
+      this, &Calc::cb_buttonClicked,
+      button_no[key]
     );
 
     calculator_buttons[button(key)] = btn;
@@ -364,10 +364,9 @@ void Calc::onClose (finalcut::FCloseEvent* ev)
 }
 
 //----------------------------------------------------------------------
-void Calc::cb_buttonClicked (const finalcut::FWidget*, FDataPtr data)
+void Calc::cb_buttonClicked (Calc::button key)
 {
   lDouble& x = getValue();
-  const Calc::button& key = *(static_cast<Calc::button*>(data));
 
   // Call the key function
   key_map[key](x);
diff --git a/examples/checklist.cpp b/examples/checklist.cpp
index 9db553cc..6304866a 100644
--- a/examples/checklist.cpp
+++ b/examples/checklist.cpp
@@ -64,7 +64,7 @@ class CheckList final : public finalcut::FDialog
     void onClose (finalcut::FCloseEvent*) override;
 
     // Callback method
-    void cb_showList (const finalcut::FWidget*, const FDataPtr);
+    void cb_showList();
 
     // Data members
     finalcut::FListView  listView{this};
@@ -110,7 +110,7 @@ CheckList::CheckList (finalcut::FWidget* parent)
   listView.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &CheckList::cb_showList)
+    this, &CheckList::cb_showList
   );
 }
 
@@ -168,7 +168,7 @@ void CheckList::onClose (finalcut::FCloseEvent* ev)
 }
 
 //----------------------------------------------------------------------
-void CheckList::cb_showList (const finalcut::FWidget*, const FDataPtr)
+void CheckList::cb_showList()
 {
   auto iter = listView.beginOfList();
   finalcut::FString shopping_list{};
diff --git a/examples/choice.cpp b/examples/choice.cpp
index d84deafd..7ccd610e 100644
--- a/examples/choice.cpp
+++ b/examples/choice.cpp
@@ -31,17 +31,16 @@ using finalcut::FSize;
 typedef std::shared_ptr<finalcut::FRadioButton> FRadioButtonPtr;
 
 // Function prototypes
-void cb_quit (const finalcut::FWidget*, FDataPtr);
+void cb_quit (finalcut::FDialog&);
 void populateChoice (std::vector<FRadioButtonPtr>&, finalcut::FButtonGroup&);
 void preset (std::vector<FRadioButtonPtr>&);
 
 //----------------------------------------------------------------------
 // Callback functions
 //----------------------------------------------------------------------
-void cb_quit (const finalcut::FWidget*, FDataPtr data)
+void cb_quit (finalcut::FDialog& dlg)
 {
-  auto dlg = static_cast<finalcut::FDialog*>(data);
-  dlg->close();
+  dlg.close();
 }
 
 //----------------------------------------------------------------------
@@ -141,7 +140,7 @@ int main (int argc, char* argv[])
     (
       "clicked",
       &cb_quit,
-      &dgl
+      std::ref(dgl)
     );
 
     // Show the dialog
diff --git a/examples/dialog.cpp b/examples/dialog.cpp
index 88591909..eef1e272 100644
--- a/examples/dialog.cpp
+++ b/examples/dialog.cpp
@@ -26,15 +26,14 @@ using finalcut::FPoint;
 using finalcut::FSize;
 
 // function prototype
-void cb_quit (const finalcut::FWidget*, FDataPtr);
+void cb_quit (finalcut::FApplication&);
 
 
 //----------------------------------------------------------------------
 // callback function
 //----------------------------------------------------------------------
-void cb_quit (const finalcut::FWidget*, FDataPtr data)
+void cb_quit (finalcut::FApplication& app)
 {
-  const auto& app = *(static_cast<finalcut::FApplication*>(data));
   app.quit();
 }
 
@@ -77,7 +76,7 @@ int main (int argc, char* argv[])
   (
     "clicked",
     &cb_quit,
-    &app
+    std::ref(app)
   );
 
   // Set dialog object as main widget
diff --git a/examples/fullwidth-character.cpp b/examples/fullwidth-character.cpp
index 87ce8204..b375e210 100644
--- a/examples/fullwidth-character.cpp
+++ b/examples/fullwidth-character.cpp
@@ -105,16 +105,14 @@ int main (int argc, char* argv[])
 
   // Callback lambda expressions
   auto cb_exit = \
-      [] (const finalcut::FWidget*, FDataPtr data)
+      [] (finalcut::FApplication& a)
       {
-        auto a = static_cast<finalcut::FApplication*>(data);
-        a->quit();
+        a.quit();
       };
 
   auto cb_tooltip = \
-      [] (const finalcut::FWidget*, FDataPtr data)
+      [] (finalcut::FApplication* a)
       {
-        auto a = static_cast<finalcut::FApplication*>(data);
         finalcut::FToolTip tooltip(a);
         tooltip.setText (full("A tooltip with\ncharacters\n"
                               "in full-width\nfor 3 seconds"));
@@ -123,9 +121,9 @@ int main (int argc, char* argv[])
       };
 
   // Connect the signals with the callback lambda expressions
-  btn.addCallback ("clicked", cb_exit, &app);
-  Exit.addCallback ("clicked", cb_exit, &app);
-  Quit.addCallback ("clicked", cb_exit, &app);
+  btn.addCallback ("clicked", cb_exit, std::ref(app));
+  Exit.addCallback ("clicked", cb_exit, std::ref(app));
+  Quit.addCallback ("clicked", cb_exit, std::ref(app));
   key_F1.addCallback ("activate", cb_tooltip, &app);
 
   // Set dialog object as main widget
diff --git a/examples/input-dialog.cpp b/examples/input-dialog.cpp
index cd6796b9..b1438d8b 100644
--- a/examples/input-dialog.cpp
+++ b/examples/input-dialog.cpp
@@ -26,33 +26,30 @@ using finalcut::FPoint;
 using finalcut::FSize;
 
 // function prototypes
-void cb_quit (const finalcut::FWidget*, FDataPtr);
-void cb_publish (finalcut::FWidget*, FDataPtr);
+void cb_quit (finalcut::FApplication&);
+void cb_publish (finalcut::FCheckBox&, finalcut::FCheckBox&);
 
 
 //----------------------------------------------------------------------
 // callback functions
 //----------------------------------------------------------------------
-void cb_quit (const finalcut::FWidget*, FDataPtr data)
+void cb_quit (finalcut::FApplication& app)
 {
-  auto app = static_cast<finalcut::FApplication*>(data);
-  app->quit();
+  app.quit();
 }
 
-void cb_publish (finalcut::FWidget* widget, FDataPtr data)
+//----------------------------------------------------------------------
+void cb_publish (finalcut::FCheckBox& cbox1, finalcut::FCheckBox& cbox2)
 {
-  auto cbox1 = static_cast<finalcut::FCheckBox*>(widget);
-  auto cbox2 = static_cast<finalcut::FCheckBox*>(data);
-
-  if ( cbox1->isChecked() )
-    cbox2->setEnable();
+  if ( cbox1.isChecked() )
+    cbox2.setEnable();
   else
   {
-    cbox2->unsetChecked();
-    cbox2->setDisable();
+    cbox2.unsetChecked();
+    cbox2.setDisable();
   }
 
-  cbox2->redraw();
+  cbox2.redraw();
 }
 
 //----------------------------------------------------------------------
@@ -124,7 +121,8 @@ int main (int argc, char* argv[])
   (
     "clicked",
     &cb_publish,
-    &check2
+    std::ref(check1),
+    std::ref(check2)
   );
 
   // Connect the button signal "clicked" with the callback function
@@ -132,7 +130,7 @@ int main (int argc, char* argv[])
   (
     "clicked",
     &cb_quit,
-    &app
+    std::ref(app)
   );
 
   // Set dialog object as main widget
diff --git a/examples/listbox.cpp b/examples/listbox.cpp
index adb41eb9..da66a48b 100644
--- a/examples/listbox.cpp
+++ b/examples/listbox.cpp
@@ -157,7 +157,9 @@ Listbox::Listbox (FWidget* parent)
   Quit.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &FApplication::cb_exitApp)
+    finalcut::getFApplication(),
+    &finalcut::FApplication::cb_exitApp,
+    this
   );
 }
 
diff --git a/examples/listview.cpp b/examples/listview.cpp
index 6b1fbcdb..6f7c905a 100644
--- a/examples/listview.cpp
+++ b/examples/listview.cpp
@@ -59,7 +59,7 @@ class Listview final : public finalcut::FDialog
     void onClose (finalcut::FCloseEvent*) override;
 
     // Callback method
-    void cb_showInMessagebox (const finalcut::FWidget*, const FDataPtr);
+    void cb_showInMessagebox();
 
     // Data members
     finalcut::FListView listView{this};
@@ -111,13 +111,15 @@ Listview::Listview (finalcut::FWidget* parent)
   Quit.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &finalcut::FApplication::cb_exitApp)
+    finalcut::getFApplication(),
+    &finalcut::FApplication::cb_exitApp,
+    this
   );
 
   listView.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &Listview::cb_showInMessagebox)
+    this, &Listview::cb_showInMessagebox
   );
 }
 
@@ -187,7 +189,7 @@ void Listview::onClose (finalcut::FCloseEvent* ev)
 }
 
 //----------------------------------------------------------------------
-void Listview::cb_showInMessagebox (const finalcut::FWidget*, const FDataPtr)
+void Listview::cb_showInMessagebox()
 {
   const auto& item = listView.getCurrentItem();
   finalcut::FMessageBox info ( "Weather in " + item->getText(1)
diff --git a/examples/menu.cpp b/examples/menu.cpp
index 39bdce23..934c3916 100644
--- a/examples/menu.cpp
+++ b/examples/menu.cpp
@@ -61,7 +61,7 @@ class Menu final : public finalcut::FDialog
     void onClose (finalcut::FCloseEvent*) override;
 
     // Callback method
-    void cb_message (finalcut::FWidget*, const FDataPtr);
+    void cb_message (finalcut::FMenuItem*);
 
     // Data members
     finalcut::FString        line{13, fc::BoxDrawingsHorizontal};
@@ -183,7 +183,9 @@ void Menu::configureFileMenuItems()
   Quit.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &finalcut::FApplication::cb_exitApp)
+    finalcut::getFApplication(),
+    &finalcut::FApplication::cb_exitApp,
+    this
   );
 }
 
@@ -275,7 +277,8 @@ void Menu::defaultCallback (const finalcut::FMenuList* mb)
       item->addCallback
       (
         "clicked",
-        F_METHOD_CALLBACK (this, &Menu::cb_message)
+        this, &Menu::cb_message,
+        item
       );
 
       // Call sub-menu
@@ -302,9 +305,8 @@ void Menu::onClose (finalcut::FCloseEvent* ev)
 }
 
 //----------------------------------------------------------------------
-void Menu::cb_message (finalcut::FWidget* widget, const FDataPtr)
+void Menu::cb_message (finalcut::FMenuItem* menuitem)
 {
-  const auto& menuitem = static_cast<finalcut::FMenuItem*>(widget);
   auto text = menuitem->getText();
   text = text.replace('&', "");
   finalcut::FMessageBox::info ( this
diff --git a/examples/mouse.cpp b/examples/mouse.cpp
index 0992392b..e986e937 100644
--- a/examples/mouse.cpp
+++ b/examples/mouse.cpp
@@ -353,7 +353,7 @@ class MouseDraw final : public finalcut::FDialog
     void onMouseMove (finalcut::FMouseEvent*) override;
 
     // Callback methods
-    void cb_colorChanged (const finalcut::FWidget*, const FDataPtr);
+    void cb_colorChanged();
 
     // Data members
     FTermArea*   canvas{nullptr};
@@ -371,7 +371,7 @@ MouseDraw::MouseDraw (finalcut::FWidget* parent)
   c_chooser.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &MouseDraw::cb_colorChanged)
+    this, &MouseDraw::cb_colorChanged
   );
 
   brush.setPos (FPoint{1, 12});
@@ -572,7 +572,7 @@ void MouseDraw::onMouseMove (finalcut::FMouseEvent* ev)
 }
 
 //----------------------------------------------------------------------
-void MouseDraw::cb_colorChanged (const finalcut::FWidget*, const FDataPtr)
+void MouseDraw::cb_colorChanged()
 {
   brush.setForeground (c_chooser.getForeground());
   brush.setBackground (c_chooser.getBackground());
diff --git a/examples/scrollview.cpp b/examples/scrollview.cpp
index e45dd26e..a3b6d671 100644
--- a/examples/scrollview.cpp
+++ b/examples/scrollview.cpp
@@ -54,10 +54,10 @@ class Scrollview final : public finalcut::FScrollView
     void draw() override;
 
     // Callback methods
-    void cb_goEast (const finalcut::FWidget*, const FDataPtr);
-    void cb_goSouth (const finalcut::FWidget*, const FDataPtr);
-    void cb_goWest (const finalcut::FWidget*, const FDataPtr);
-    void cb_goNorth (const finalcut::FWidget*, const FDataPtr);
+    void cb_goEast();
+    void cb_goSouth();
+    void cb_goWest();
+    void cb_goNorth();
 
     // Data members
     wchar_t pointer_right{fc::BlackRightPointingPointer};
@@ -88,25 +88,25 @@ Scrollview::Scrollview (finalcut::FWidget* parent)
   go_east.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &Scrollview::cb_goEast)
+    this, &Scrollview::cb_goEast
   );
 
   go_south.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &Scrollview::cb_goSouth)
+    this, &Scrollview::cb_goSouth
   );
 
   go_west.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &Scrollview::cb_goWest)
+    this, &Scrollview::cb_goWest
   );
 
   go_north.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &Scrollview::cb_goNorth)
+    this, &Scrollview::cb_goNorth
   );
 }
 
@@ -150,7 +150,7 @@ void Scrollview::draw()
 }
 
 //----------------------------------------------------------------------
-void Scrollview::cb_goEast (const finalcut::FWidget*, const FDataPtr)
+void Scrollview::cb_goEast()
 {
   scrollToX (int(getScrollWidth() - getViewportWidth()) + 1);
   go_south.setFocus();
@@ -159,7 +159,7 @@ void Scrollview::cb_goEast (const finalcut::FWidget*, const FDataPtr)
 }
 
 //----------------------------------------------------------------------
-void Scrollview::cb_goSouth (const finalcut::FWidget*, const FDataPtr)
+void Scrollview::cb_goSouth()
 {
   scrollToY (int(getScrollHeight() - getViewportHeight()) + 1);
   go_west.setFocus();
@@ -168,7 +168,7 @@ void Scrollview::cb_goSouth (const finalcut::FWidget*, const FDataPtr)
 }
 
 //----------------------------------------------------------------------
-void Scrollview::cb_goWest (const finalcut::FWidget*, const FDataPtr)
+void Scrollview::cb_goWest()
 {
   scrollToX (1);
   go_north.setFocus();
@@ -177,7 +177,7 @@ void Scrollview::cb_goWest (const finalcut::FWidget*, const FDataPtr)
 }
 
 //----------------------------------------------------------------------
-void Scrollview::cb_goNorth (const finalcut::FWidget*, const FDataPtr)
+void Scrollview::cb_goNorth()
 {
   scrollToY (1);
   go_east.setFocus();
@@ -230,7 +230,9 @@ Scrollviewdemo::Scrollviewdemo (finalcut::FWidget* parent)
   quit_btn.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &Scrollviewdemo::cb_quit)
+    finalcut::getFApplication(),
+    &finalcut::FApplication::cb_exitApp,
+    this
   );
 
   // Text label
diff --git a/examples/term-attributes.cpp b/examples/term-attributes.cpp
index a40a4dd2..65ec75dd 100644
--- a/examples/term-attributes.cpp
+++ b/examples/term-attributes.cpp
@@ -58,8 +58,8 @@ class AttribDlg final : public finalcut::FDialog
     void onClose (finalcut::FCloseEvent*) override;
 
     // Callback methods
-    void cb_next (const finalcut::FWidget* = nullptr, const FDataPtr = nullptr);
-    void cb_back (const finalcut::FWidget* = nullptr, const FDataPtr = nullptr);
+    void cb_next();
+    void cb_back();
 
   private:
     // Constants
@@ -90,13 +90,13 @@ AttribDlg::AttribDlg (finalcut::FWidget* parent)
   next_button.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &AttribDlg::cb_next)
+    this, &AttribDlg::cb_next
   );
 
   back_button.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &AttribDlg::cb_back)
+    this, &AttribDlg::cb_back
   );
 }
 
@@ -143,7 +143,7 @@ void AttribDlg::onClose (finalcut::FCloseEvent* ev)
 }
 
 //----------------------------------------------------------------------
-void AttribDlg::cb_next (const finalcut::FWidget*, const FDataPtr)
+void AttribDlg::cb_next()
 {
   if ( finalcut::FTerm::isMonochron() )
     return;
@@ -159,7 +159,7 @@ void AttribDlg::cb_next (const finalcut::FWidget*, const FDataPtr)
 }
 
 //----------------------------------------------------------------------
-void AttribDlg::cb_back (const finalcut::FWidget*, const FDataPtr)
+void AttribDlg::cb_back()
 {
   if ( finalcut::FTerm::isMonochron() )
     return;
diff --git a/examples/treeview.cpp b/examples/treeview.cpp
index 1d9a5012..438ab0f3 100644
--- a/examples/treeview.cpp
+++ b/examples/treeview.cpp
@@ -386,7 +386,9 @@ Treeview::Treeview (finalcut::FWidget* parent)
   Quit.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &finalcut::FApplication::cb_exitApp)
+    finalcut::getFApplication(),
+    &finalcut::FApplication::cb_exitApp,
+    this
   );
 
   initialized = true;
diff --git a/examples/ui.cpp b/examples/ui.cpp
index ca97fe9f..6676d9ca 100644
--- a/examples/ui.cpp
+++ b/examples/ui.cpp
@@ -63,9 +63,9 @@ class ProgressDialog final : public finalcut::FDialog
     void onTimer (finalcut::FTimerEvent*) override;
 
     // Callback methods
-    void cb_reset_bar (const finalcut::FWidget*, const FDataPtr);
-    void cb_more_bar (const finalcut::FWidget*, const FDataPtr);
-    void cb_exit_bar (const finalcut::FWidget*, const FDataPtr);
+    void cb_reset_bar();
+    void cb_more_bar();
+    void cb_exit_bar();
 
     // Data members
     finalcut::FProgressbar progressBar{this};
@@ -107,19 +107,19 @@ ProgressDialog::ProgressDialog (finalcut::FWidget* parent)
   reset.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &ProgressDialog::cb_reset_bar)
+    this, &ProgressDialog::cb_reset_bar
   );
 
   more.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &ProgressDialog::cb_more_bar)
+    this, &ProgressDialog::cb_more_bar
   );
 
   quit.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &ProgressDialog::cb_exit_bar)
+    this, &ProgressDialog::cb_exit_bar
   );
 }
 
@@ -166,13 +166,13 @@ void ProgressDialog::onTimer (finalcut::FTimerEvent*)
 }
 
 //----------------------------------------------------------------------
-void ProgressDialog::cb_reset_bar (const finalcut::FWidget*, const FDataPtr)
+void ProgressDialog::cb_reset_bar()
 {
   progressBar.reset();
 }
 
 //----------------------------------------------------------------------
-void ProgressDialog::cb_more_bar (const finalcut::FWidget*, const FDataPtr)
+void ProgressDialog::cb_more_bar()
 {
   auto p = progressBar.getPercentage();
   p++;
@@ -180,7 +180,7 @@ void ProgressDialog::cb_more_bar (const finalcut::FWidget*, const FDataPtr)
 }
 
 //----------------------------------------------------------------------
-void ProgressDialog::cb_exit_bar (const finalcut::FWidget*, const FDataPtr)
+void ProgressDialog::cb_exit_bar()
 {
   close();
 }
@@ -293,22 +293,24 @@ class MyDialog final : public finalcut::FDialog
     void onClose (finalcut::FCloseEvent*) override;
 
     // Callback methods
-    void cb_noFunctionMsg (finalcut::FWidget*, const FDataPtr);
-    void cb_about (const finalcut::FWidget*, const FDataPtr);
-    void cb_terminfo (const finalcut::FWidget*, const FDataPtr);
-    void cb_drives (const finalcut::FWidget*, const FDataPtr);
-    void cb_cutClipboard (const finalcut::FWidget*, const FDataPtr);
-    void cb_copyClipboard (const finalcut::FWidget*, const FDataPtr);
-    void cb_pasteClipboard (const finalcut::FWidget*, const FDataPtr);
-    void cb_clearInput (const finalcut::FWidget*, const FDataPtr);
-    void cb_switchTheme (const finalcut::FWidget*, const FDataPtr) const;
-    void cb_input2buttonText (finalcut::FWidget*, FDataPtr) const;
-    void cb_setTitlebar (finalcut::FWidget*, const FDataPtr);
-    void cb_showProgressBar (const finalcut::FWidget*, const FDataPtr);
-    void cb_updateNumber (finalcut::FWidget*, FDataPtr) const;
-    void cb_activateButton (finalcut::FWidget*, FDataPtr) const;
-    void cb_view (const finalcut::FWidget*, FDataPtr);
-    void cb_setInput (finalcut::FWidget*, FDataPtr) const;
+    void cb_noFunctionMsg (finalcut::FButton&);
+    void cb_about();
+    void cb_terminfo();
+    void cb_drives();
+    void cb_cutClipboard();
+    void cb_copyClipboard();
+    void cb_pasteClipboard();
+    void cb_clearInput();
+    void cb_switchTheme (const finalcut::FCheckMenuItem*) const;
+    void cb_input2buttonText ( finalcut::FButton&
+                             , const finalcut::FLineEdit& ) const;
+    void cb_setTitlebar (finalcut::FLineEdit&);
+    void cb_showProgressBar();
+    void cb_updateNumber (finalcut::FListBox&, finalcut::FLabel&) const;
+    void cb_activateButton ( finalcut::FRadioButton&
+                           , finalcut::FButton& ) const;
+    void cb_view (finalcut::FMenuItem*);
+    void cb_setInput (finalcut::FListBox&, finalcut::FLineEdit&) const;
 
     // Data members
     bool                      initialized{false};
@@ -448,35 +450,38 @@ void MyDialog::initFileMenuCallbacks()
   Open.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &MyDialog::cb_view)
+    this, &MyDialog::cb_view,
+    nullptr
   );
 
   Quit.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &finalcut::FApplication::cb_exitApp)
+    finalcut::getFApplication(),
+    &finalcut::FApplication::cb_exitApp,
+    this
   );
 
   // System files submenu
   File1.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &MyDialog::cb_view),
-    static_cast<FDataPtr>(&File1)
+    this, &MyDialog::cb_view,
+    &File1
   );
 
   File2.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &MyDialog::cb_view),
-    static_cast<FDataPtr>(&File2)
+    this, &MyDialog::cb_view,
+    &File2
   );
 
   File3.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &MyDialog::cb_view),
-    static_cast<FDataPtr>(&File3)
+    this, &MyDialog::cb_view,
+    &File3
   );
 }
 
@@ -487,25 +492,25 @@ void MyDialog::initEditMenuCallbacks()
   Cut.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &MyDialog::cb_cutClipboard)
+    this, &MyDialog::cb_cutClipboard
   );
 
   Copy.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &MyDialog::cb_copyClipboard)
+    this, &MyDialog::cb_copyClipboard
   );
 
   Paste.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &MyDialog::cb_pasteClipboard)
+    this, &MyDialog::cb_pasteClipboard
   );
 
   Clear.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &MyDialog::cb_clearInput)
+    this, &MyDialog::cb_clearInput
   );
 }
 
@@ -516,19 +521,20 @@ void MyDialog::initViewMenuCallbacks()
   Env.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &MyDialog::cb_terminfo)
+    this, &MyDialog::cb_terminfo
   );
 
   Drive.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &MyDialog::cb_drives)
+    this, &MyDialog::cb_drives
   );
 
   Theme.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &MyDialog::cb_switchTheme)
+    this, &MyDialog::cb_switchTheme,
+    &Theme
   );
 }
 
@@ -538,7 +544,7 @@ void MyDialog::initHelpMenuCallback()
   Help.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &MyDialog::cb_about)
+    this, &MyDialog::cb_about
   );
 }
 
@@ -550,19 +556,22 @@ void MyDialog::initStatusBarCallbacks()
   key_F1.addCallback
   (
     "activate",
-    F_METHOD_CALLBACK (this, &MyDialog::cb_about)
+    this, &MyDialog::cb_about
   );
 
   key_F2.addCallback
   (
     "activate",
-    F_METHOD_CALLBACK (this, &MyDialog::cb_view)
+    this, &MyDialog::cb_view,
+    nullptr
   );
 
   key_F3.addCallback
   (
     "activate",
-    F_METHOD_CALLBACK (this, &finalcut::FApplication::cb_exitApp)
+    finalcut::getFApplication(),
+    &finalcut::FApplication::cb_exitApp,
+    this
   );
 }
 
@@ -627,19 +636,22 @@ void MyDialog::initFlatButtons()
   MyButton1.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &MyDialog::cb_noFunctionMsg)
+    this, &MyDialog::cb_noFunctionMsg,
+    std::ref(MyButton1)
   );
 
   MyButton2.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &MyDialog::cb_noFunctionMsg)
+    this, &MyDialog::cb_noFunctionMsg,
+    std::ref(MyButton2)
   );
 
   MyButton3.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &MyDialog::cb_noFunctionMsg)
+    this, &MyDialog::cb_noFunctionMsg,
+    std::ref(MyButton3)
   );
 }
 
@@ -693,20 +705,22 @@ void MyDialog::initButtons()
   MyButton4.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &MyDialog::cb_input2buttonText),
-    static_cast<FDataPtr>(&myLineEdit)
+    this, &MyDialog::cb_input2buttonText,
+    std::ref(MyButton4), std::cref(myLineEdit)
   );
 
   MyButton5.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &MyDialog::cb_showProgressBar)
+    this, &MyDialog::cb_showProgressBar
   );
 
   MyButton6.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &finalcut::FApplication::cb_exitApp)
+    finalcut::getFApplication(),
+    &finalcut::FApplication::cb_exitApp,
+    this
   );
 }
 
@@ -739,28 +753,29 @@ void MyDialog::initWidgetsCallbacks()
   myLineEdit.addCallback
   (
     "activate",  // e.g. on <Enter>
-    F_METHOD_CALLBACK (this, &MyDialog::cb_setTitlebar)
+    this, &MyDialog::cb_setTitlebar,
+    std::ref(myLineEdit)
   );
 
   radio1.addCallback
   (
     "toggled",
-    F_METHOD_CALLBACK (this, &MyDialog::cb_activateButton),
-    static_cast<FDataPtr>(&MyButton5)
+    this, &MyDialog::cb_activateButton,
+    std::ref(radio1), std::ref(MyButton5)
   );
 
   myList.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &MyDialog::cb_setInput),
-    static_cast<FDataPtr>(&myLineEdit)
+    this, &MyDialog::cb_setInput,
+    std::ref(myList), std::ref(myLineEdit)
   );
 
   myList.addCallback
   (
     "row-selected",
-    F_METHOD_CALLBACK (this, &MyDialog::cb_updateNumber),
-    static_cast<FDataPtr>(&tagged_count)
+    this, &MyDialog::cb_updateNumber,
+    std::ref(myList), std::ref(tagged_count)
   );
 }
 
@@ -789,9 +804,8 @@ void MyDialog::onClose (finalcut::FCloseEvent* ev)
 }
 
 //----------------------------------------------------------------------
-void MyDialog::cb_noFunctionMsg (finalcut::FWidget* widget, const FDataPtr)
+void MyDialog::cb_noFunctionMsg (finalcut::FButton& button)
 {
-  auto& button = *(static_cast<finalcut::FButton*>(widget));
   auto text = button.getText();
   text = text.replace('&', "");
   finalcut::FMessageBox::error ( this
@@ -800,7 +814,7 @@ void MyDialog::cb_noFunctionMsg (finalcut::FWidget* widget, const FDataPtr)
 }
 
 //----------------------------------------------------------------------
-void MyDialog::cb_about (const finalcut::FWidget*, const FDataPtr)
+void MyDialog::cb_about()
 {
   constexpr char libver[] = F_VERSION;
   const finalcut::FString line(2, fc::BoxDrawingsHorizontal);
@@ -815,7 +829,7 @@ void MyDialog::cb_about (const finalcut::FWidget*, const FDataPtr)
 }
 
 //----------------------------------------------------------------------
-void MyDialog::cb_terminfo (const finalcut::FWidget*, const FDataPtr)
+void MyDialog::cb_terminfo()
 {
   const auto x = getDesktopWidth();
   const auto y = getDesktopHeight();
@@ -836,7 +850,7 @@ void MyDialog::cb_terminfo (const finalcut::FWidget*, const FDataPtr)
 }
 
 //----------------------------------------------------------------------
-void MyDialog::cb_drives (const finalcut::FWidget*, const FDataPtr)
+void MyDialog::cb_drives()
 {
   finalcut::FMessageBox info2 \
   (
@@ -887,7 +901,7 @@ void MyDialog::cb_drives (const finalcut::FWidget*, const FDataPtr)
 }
 
 //----------------------------------------------------------------------
-void MyDialog::cb_cutClipboard (const finalcut::FWidget*, const FDataPtr)
+void MyDialog::cb_cutClipboard()
 {
   clipboard = myLineEdit.getText();
   myLineEdit.clear();
@@ -895,20 +909,20 @@ void MyDialog::cb_cutClipboard (const finalcut::FWidget*, const FDataPtr)
 }
 
 //----------------------------------------------------------------------
-void MyDialog::cb_copyClipboard (const finalcut::FWidget*, const FDataPtr)
+void MyDialog::cb_copyClipboard()
 {
   clipboard = myLineEdit.getText();
 }
 
 //----------------------------------------------------------------------
-void MyDialog::cb_pasteClipboard (const finalcut::FWidget*, const FDataPtr)
+void MyDialog::cb_pasteClipboard()
 {
   myLineEdit = clipboard;
   myLineEdit.redraw();
 }
 
 //----------------------------------------------------------------------
-void MyDialog::cb_clearInput (const finalcut::FWidget*, const FDataPtr)
+void MyDialog::cb_clearInput()
 {
   clipboard.clear();
   myLineEdit.clear();
@@ -916,11 +930,9 @@ void MyDialog::cb_clearInput (const finalcut::FWidget*, const FDataPtr)
 }
 
 //----------------------------------------------------------------------
-void MyDialog::cb_switchTheme (const finalcut::FWidget* widget, const FDataPtr) const
+void MyDialog::cb_switchTheme (const finalcut::FCheckMenuItem* check_menu) const
 {
-  const auto& check_menu = *(static_cast<const finalcut::FCheckMenuItem*>(widget));
-
-  if ( check_menu.isChecked() )
+  if ( check_menu->isChecked() )
     finalcut::FApplication::setDarkTheme();
   else
     finalcut::FApplication::setDefaultTheme();
@@ -931,18 +943,16 @@ void MyDialog::cb_switchTheme (const finalcut::FWidget* widget, const FDataPtr)
 }
 
 //----------------------------------------------------------------------
-void MyDialog::cb_input2buttonText (finalcut::FWidget* widget, FDataPtr data) const
+void MyDialog::cb_input2buttonText ( finalcut::FButton& button
+                                   , const finalcut::FLineEdit& lineedit ) const
 {
-  auto& button = *(static_cast<finalcut::FButton*>(widget));
-  const auto& lineedit = *(static_cast<finalcut::FLineEdit*>(data));
   button.setText(lineedit.getText());
   button.redraw();
 }
 
 //----------------------------------------------------------------------
-void MyDialog::cb_setTitlebar (finalcut::FWidget* widget, const FDataPtr)
+void MyDialog::cb_setTitlebar (finalcut::FLineEdit& lineedit)
 {
-  const auto& lineedit = *(static_cast<finalcut::FLineEdit*>(widget));
   finalcut::FString title{};
   lineedit >> title;
   finalcut::FTerm::setTermTitle (title);
@@ -951,17 +961,16 @@ void MyDialog::cb_setTitlebar (finalcut::FWidget* widget, const FDataPtr)
 }
 
 //----------------------------------------------------------------------
-void MyDialog::cb_showProgressBar (const finalcut::FWidget*, const FDataPtr)
+void MyDialog::cb_showProgressBar()
 {
   auto p_dgl = new ProgressDialog(this);
   p_dgl->show();
 }
 
 //----------------------------------------------------------------------
-void MyDialog::cb_updateNumber (finalcut::FWidget* widget, FDataPtr data) const
+void MyDialog::cb_updateNumber ( finalcut::FListBox& list
+                               , finalcut::FLabel& num) const
 {
-  const auto& list = *(static_cast<finalcut::FListBox*>(widget));
-  auto& num = *(static_cast<finalcut::FLabel*>(data));
   const auto count = list.getCount();
   int select_num = 0;
 
@@ -975,11 +984,9 @@ void MyDialog::cb_updateNumber (finalcut::FWidget* widget, FDataPtr data) const
 }
 
 //----------------------------------------------------------------------
-void MyDialog::cb_activateButton (finalcut::FWidget* widget, FDataPtr data) const
+void MyDialog::cb_activateButton ( finalcut::FRadioButton& rb
+                                 , finalcut::FButton& button) const
 {
-  const auto& rb = *(static_cast<finalcut::FRadioButton*>(widget));
-  auto& button = *(static_cast<finalcut::FButton*>(data));
-
   if ( rb.isChecked() )
     button.setEnable();
   else
@@ -989,10 +996,9 @@ void MyDialog::cb_activateButton (finalcut::FWidget* widget, FDataPtr data) cons
 }
 
 //----------------------------------------------------------------------
-void MyDialog::cb_view (const finalcut::FWidget*, FDataPtr data)
+void MyDialog::cb_view (finalcut::FMenuItem* item)
 {
   finalcut::FString file{};
-  const auto& item = static_cast<finalcut::FMenuItem*>(data);
 
   if ( item && ! item->getText().isEmpty() )
     file = item->getText();
@@ -1026,11 +1032,10 @@ void MyDialog::cb_view (const finalcut::FWidget*, FDataPtr data)
 }
 
 //----------------------------------------------------------------------
-void MyDialog::cb_setInput (finalcut::FWidget* widget, FDataPtr data) const
+void MyDialog::cb_setInput ( finalcut::FListBox& listbox
+                           , finalcut::FLineEdit& lineedit) const
 {
-  auto& ListBox = *(static_cast<finalcut::FListBox*>(widget));
-  auto& lineedit = *(static_cast<finalcut::FLineEdit*>(data));
-  lineedit = ListBox.getItem(ListBox.currentItem()).getText();
+  lineedit = listbox.getItem(listbox.currentItem()).getText();
   lineedit.redraw();
 }
 
diff --git a/examples/watch.cpp b/examples/watch.cpp
index 53c4a43c..92359dc6 100644
--- a/examples/watch.cpp
+++ b/examples/watch.cpp
@@ -54,8 +54,8 @@ class Watch final : public finalcut::FDialog
     void onClose (finalcut::FCloseEvent*) override;
 
     // Callback methods
-    void cb_clock (const finalcut::FWidget*, const FDataPtr);
-    void cb_seconds (const finalcut::FWidget*, const FDataPtr);
+    void cb_clock();
+    void cb_seconds();
 
   protected:
     // Method
@@ -99,21 +99,23 @@ Watch::Watch (FWidget* parent)
   clock_sw.addCallback
   (
     "toggled",
-    F_METHOD_CALLBACK (this, &Watch::cb_clock)
+    this, &Watch::cb_clock
   );
 
   // Connect switch signal "toggled" with a callback member function
   seconds_sw.addCallback
   (
     "toggled",
-    F_METHOD_CALLBACK (this, &Watch::cb_seconds)
+    this, &Watch::cb_seconds
   );
 
   // Connect button signal "clicked" with a callback member function
   quit_btn.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &finalcut::FApplication::cb_exitApp)
+    finalcut::getFApplication(),
+    &finalcut::FApplication::cb_exitApp,
+    this
   );
 }
 
@@ -152,7 +154,7 @@ void Watch::onClose (finalcut::FCloseEvent* ev)
 }
 
 //----------------------------------------------------------------------
-void Watch::cb_clock (const finalcut::FWidget*, const FDataPtr)
+void Watch::cb_clock()
 {
   if ( clock_sw.isChecked() )
   {
@@ -168,7 +170,7 @@ void Watch::cb_clock (const finalcut::FWidget*, const FDataPtr)
 }
 
 //----------------------------------------------------------------------
-void Watch::cb_seconds (const finalcut::FWidget*, const FDataPtr)
+void Watch::cb_seconds()
 {
   if ( seconds_sw.isChecked() )
     sec = true;
diff --git a/examples/windows.cpp b/examples/windows.cpp
index 27fa27b6..3c481407 100644
--- a/examples/windows.cpp
+++ b/examples/windows.cpp
@@ -176,10 +176,6 @@ class Window final : public finalcut::FDialog
     Window& operator = (const Window&) = delete;
 
   private:
-    // Typedefs
-    typedef void (Window::*WindowCallback)(const finalcut::FWidget*, const FDataPtr);
-    typedef void (finalcut::FApplication::*FAppCallback)(const finalcut::FWidget*, const FDataPtr);
-
     struct win_data
     {
         // Constructor
@@ -201,8 +197,9 @@ class Window final : public finalcut::FDialog
     void configureDialogButtons();
     void activateWindow (finalcut::FDialog*);
     void adjustSize() override;
-    template<typename CallbackT>
-    void addClickedCallback (finalcut::FWidget*, CallbackT);
+    template<typename InstanceT, typename CallbackT, typename... Args>
+    void addClickedCallback ( finalcut::FWidget*
+                            , InstanceT&&, CallbackT&&, Args&&... );
     template <typename IteratorT>
     finalcut::FDialog* getNext (IteratorT);
     template <typename IteratorT>
@@ -212,11 +209,11 @@ class Window final : public finalcut::FDialog
     void onClose (finalcut::FCloseEvent*) override;
 
     // Callback methods
-    void cb_createWindows (const finalcut::FWidget*, const FDataPtr);
-    void cb_closeWindows (const finalcut::FWidget*, const FDataPtr);
-    void cb_next (const finalcut::FWidget*, const FDataPtr);
-    void cb_previous (const finalcut::FWidget*, const FDataPtr);
-    void cb_destroyWindow (const finalcut::FWidget*, FDataPtr) const;
+    void cb_createWindows();
+    void cb_closeWindows();
+    void cb_next();
+    void cb_previous();
+    void cb_destroyWindow (win_data*) const;
 
     // Data members
     std::vector<win_data*>    windows{};
@@ -277,7 +274,7 @@ Window::~Window()
 
     // Remove all callbacks before Window::cb_destroyWindow() will be called
     if ( win_dat->is_open && win_dat->dgl )
-      win_dat->dgl->delAllCallbacks();
+      win_dat->dgl->delCallback();
 
     delete win_dat;
     iter = windows.erase(iter);
@@ -300,11 +297,14 @@ void Window::configureFileMenuItems()
   Quit.setStatusbarMessage ("Exit the program");
 
   // Add menu item callback
-  addClickedCallback (&New, &Window::cb_createWindows);
-  addClickedCallback (&Close, &Window::cb_closeWindows);
-  addClickedCallback (&Next, &Window::cb_next);
-  addClickedCallback (&Previous, &Window::cb_previous);
-  addClickedCallback (&Quit, &finalcut::FApplication::cb_exitApp);
+  addClickedCallback (&New, this, &Window::cb_createWindows);
+  addClickedCallback (&Close, this, &Window::cb_closeWindows);
+  addClickedCallback (&Next, this, &Window::cb_next);
+  addClickedCallback (&Previous, this, &Window::cb_previous);
+  addClickedCallback ( &Quit
+                     , finalcut::getFApplication()
+                     , &finalcut::FApplication::cb_exitApp
+                     , this );
 }
 
 //----------------------------------------------------------------------
@@ -319,9 +319,12 @@ void Window::configureDialogButtons()
   QuitButton.setText (L"&Quit");
 
   // Add button callback
-  addClickedCallback (&CreateButton, &Window::cb_createWindows);
-  addClickedCallback (&CloseButton, &Window::cb_closeWindows);
-  addClickedCallback (&QuitButton, &finalcut::FApplication::cb_exitApp);
+  addClickedCallback (&CreateButton, this, &Window::cb_createWindows);
+  addClickedCallback (&CloseButton, this, &Window::cb_closeWindows);
+  addClickedCallback ( &QuitButton
+                     , finalcut::getFApplication()
+                     , &finalcut::FApplication::cb_exitApp
+                     , this );
 }
 
 //----------------------------------------------------------------------
@@ -373,17 +376,18 @@ void Window::adjustSize()
 }
 
 //----------------------------------------------------------------------
-template<typename CallbackT>
+template<typename InstanceT, typename CallbackT, typename... Args>
 void Window::addClickedCallback ( finalcut::FWidget* widget
-                                , CallbackT call )
+                                , InstanceT&& instance
+                                , CallbackT&& callback
+                                , Args&&... args )
 {
-  FMemberCallback callback
-      = reinterpret_cast<FMemberCallback>(call);
-
   widget->addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, callback)
+    std::bind ( std::forward<CallbackT>(callback)
+              , std::forward<InstanceT>(instance)
+              , std::forward<Args>(args)... )
   );
 }
 
@@ -439,7 +443,7 @@ void Window::onClose (finalcut::FCloseEvent* ev)
 }
 
 //----------------------------------------------------------------------
-void Window::cb_createWindows (const finalcut::FWidget*, const FDataPtr)
+void Window::cb_createWindows()
 {
   const auto& first = windows.begin();
   auto iter = first;
@@ -468,8 +472,8 @@ void Window::cb_createWindows (const finalcut::FWidget*, const FDataPtr)
       win->addCallback
       (
         "destroy",
-        F_METHOD_CALLBACK (this, &Window::cb_destroyWindow),
-        static_cast<FDataPtr>(win_dat)
+        this, &Window::cb_destroyWindow,
+        win_dat
       );
     }
 
@@ -480,7 +484,7 @@ void Window::cb_createWindows (const finalcut::FWidget*, const FDataPtr)
 }
 
 //----------------------------------------------------------------------
-void Window::cb_closeWindows (const finalcut::FWidget*, const FDataPtr)
+void Window::cb_closeWindows()
 {
   if ( ! getDialogList() || getDialogList()->empty() )
     return;
@@ -500,7 +504,7 @@ void Window::cb_closeWindows (const finalcut::FWidget*, const FDataPtr)
 }
 
 //----------------------------------------------------------------------
-void Window::cb_next (const finalcut::FWidget*, const FDataPtr)
+void Window::cb_next()
 {
   if ( ! getDialogList() || getDialogList()->empty() )
     return;
@@ -520,7 +524,7 @@ void Window::cb_next (const finalcut::FWidget*, const FDataPtr)
 }
 
 //----------------------------------------------------------------------
-void Window::cb_previous (const finalcut::FWidget*, const FDataPtr)
+void Window::cb_previous()
 {
   if ( ! getDialogList() || getDialogList()->empty() )
     return;
@@ -542,10 +546,8 @@ void Window::cb_previous (const finalcut::FWidget*, const FDataPtr)
 }
 
 //----------------------------------------------------------------------
-void Window::cb_destroyWindow (const finalcut::FWidget*, FDataPtr data) const
+void Window::cb_destroyWindow (win_data* win_dat) const
 {
-  auto win_dat = static_cast<win_data*>(data);
-
   if ( win_dat )
   {
     win_dat->is_open = false;
diff --git a/src/Makefile.am b/src/Makefile.am
index 18aef3d5..6eb26cfc 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -19,6 +19,7 @@ libfinal_la_SOURCES = \
 	flineedit.cpp \
 	fbutton.cpp \
 	fbuttongroup.cpp \
+	fcallback.cpp \
 	ftogglebutton.cpp \
 	fradiobutton.cpp \
 	fcheckbox.cpp \
@@ -85,6 +86,7 @@ finalcutinclude_HEADERS = \
 	include/final/fapplication.h \
 	include/final/fbutton.h \
 	include/final/fbuttongroup.h \
+	include/final/fcallback.h \
 	include/final/fcheckbox.h \
 	include/final/fcolorpair.h \
 	include/final/fdata.h \
diff --git a/src/Makefile.clang b/src/Makefile.clang
index 4116e4a0..00547773 100644
--- a/src/Makefile.clang
+++ b/src/Makefile.clang
@@ -12,6 +12,7 @@ INCLUDE_HEADERS = \
 	fapplication.h \
 	fbuttongroup.h \
 	fbutton.h \
+	fcallback.h \
 	fcolorpair.h \
 	fstyle.h \
 	ftogglebutton.h \
@@ -91,6 +92,7 @@ OBJS = \
 	fpoint.o \
 	fsize.o \
 	frect.o \
+	fcallback.o \
 	fscrollbar.o \
 	fprogressbar.o \
 	flineedit.o \
diff --git a/src/Makefile.gcc b/src/Makefile.gcc
index 36222322..6ab87c5b 100644
--- a/src/Makefile.gcc
+++ b/src/Makefile.gcc
@@ -12,6 +12,7 @@ INCLUDE_HEADERS = \
 	fapplication.h \
 	fbuttongroup.h \
 	fbutton.h \
+	fcallback.h \
 	fcolorpair.h \
 	fstyle.h \
 	ftogglebutton.h \
@@ -91,6 +92,7 @@ OBJS = \
 	fpoint.o \
 	fsize.o \
 	frect.o \
+	fcallback.o \
 	fscrollbar.o \
 	fprogressbar.o \
 	flineedit.o \
diff --git a/src/fbuttongroup.cpp b/src/fbuttongroup.cpp
index 303a2a21..0a917bba 100644
--- a/src/fbuttongroup.cpp
+++ b/src/fbuttongroup.cpp
@@ -240,11 +240,11 @@ void FButtonGroup::insert (FToggleButton* button)
   button->addCallback
   (
     "toggled",
-    F_METHOD_CALLBACK (this, &FButtonGroup::cb_buttonToggled)
+    this, &FButtonGroup::cb_buttonToggled,
+    button
   );
 }
 
-//----------------------------------------------------------------------
 void FButtonGroup::remove (FToggleButton* button)
 {
   if ( ! button || buttonlist.empty() )
@@ -542,10 +542,8 @@ void FButtonGroup::directFocus()
 }
 
 //----------------------------------------------------------------------
-void FButtonGroup::cb_buttonToggled (FWidget* widget, const FDataPtr) const
+void FButtonGroup::cb_buttonToggled (FToggleButton* button) const
 {
-  const auto& button = static_cast<FToggleButton*>(widget);
-
   if ( (button && ! button->isChecked()) || buttonlist.empty() )
     return;
 
diff --git a/src/fcallback.cpp b/src/fcallback.cpp
new file mode 100644
index 00000000..2296f0af
--- /dev/null
+++ b/src/fcallback.cpp
@@ -0,0 +1,42 @@
+/***********************************************************************
+* fcallback.cpp - Implements the callback functionality                *
+*                                                                      *
+* This file is part of the FINAL CUT widget toolkit                    *
+*                                                                      *
+* Copyright 2020 Markus Gans                                           *
+*                                                                      *
+* FINAL CUT is free software; you can redistribute it and/or modify    *
+* it under the terms of the GNU Lesser General Public License as       *
+* published by the Free Software Foundation; either version 3 of       *
+* the License, or (at your option) any later version.                  *
+*                                                                      *
+* FINAL CUT is distributed in the hope that it will be useful, but     *
+* WITHOUT ANY WARRANTY; without even the implied warranty of           *
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        *
+* GNU Lesser General Public License for more details.                  *
+*                                                                      *
+* You should have received a copy of the GNU Lesser General Public     *
+* License along with this program.  If not, see                        *
+* <http://www.gnu.org/licenses/>.                                      *
+***********************************************************************/
+
+#include "final/fcallback.h"
+
+namespace finalcut
+{
+
+//----------------------------------------------------------------------
+// class FCallback
+//----------------------------------------------------------------------
+
+// constructors and destructor
+//----------------------------------------------------------------------
+FCallback::FCallback()
+{ }
+
+//----------------------------------------------------------------------
+FCallback::~FCallback()  // destructor
+{ }
+
+}  // namespace finalcut
+
diff --git a/src/fcombobox.cpp b/src/fcombobox.cpp
index 5c843fc4..43f1c0d6 100644
--- a/src/fcombobox.cpp
+++ b/src/fcombobox.cpp
@@ -508,19 +508,19 @@ void FComboBox::initCallbacks()
   input_field.addCallback
   (
     "mouse-press",
-    F_METHOD_CALLBACK (this, &FComboBox::cb_inputFieldSwitch)
+    this, &FComboBox::cb_inputFieldSwitch
   );
 
   input_field.addCallback
   (
     "mouse-move",
-    F_METHOD_CALLBACK (this, &FComboBox::cb_inputFieldHandOver)
+    this, &FComboBox::cb_inputFieldHandOver
   );
 
   list_window.list.addCallback
   (
     "row-changed",
-    F_METHOD_CALLBACK (this, &FComboBox::cb_setInputField)
+    this, &FComboBox::cb_setInputField
   );
 
   for (const auto& signal : {"row-selected", "clicked"})
@@ -528,7 +528,7 @@ void FComboBox::initCallbacks()
     list_window.list.addCallback
     (
       signal,
-      F_METHOD_CALLBACK (this, &FComboBox::cb_closeComboBox)
+      this, &FComboBox::cb_closeComboBox
     );
   }
 }
@@ -628,7 +628,7 @@ void FComboBox::processChanged()
 }
 
 //----------------------------------------------------------------------
-void FComboBox::cb_setInputField (const FWidget*, const FDataPtr)
+void FComboBox::cb_setInputField()
 {
   auto& list = list_window.list;
   const std::size_t index = list.currentItem();
@@ -638,14 +638,14 @@ void FComboBox::cb_setInputField (const FWidget*, const FDataPtr)
 }
 
 //----------------------------------------------------------------------
-void FComboBox::cb_closeComboBox (const FWidget*, const FDataPtr)
+void FComboBox::cb_closeComboBox()
 {
   hideDropDown();
   processClick();
 }
 
 //----------------------------------------------------------------------
-void FComboBox::cb_inputFieldSwitch (const FWidget*, const FDataPtr)
+void FComboBox::cb_inputFieldSwitch()
 {
   const auto& mouse = FTerm::getFMouseControl();
 
@@ -677,7 +677,7 @@ void FComboBox::cb_inputFieldSwitch (const FWidget*, const FDataPtr)
 }
 
 //----------------------------------------------------------------------
-void FComboBox::cb_inputFieldHandOver (const FWidget*, const FDataPtr)
+void FComboBox::cb_inputFieldHandOver()
 {
   const auto& mouse = FTerm::getFMouseControl();
 
diff --git a/src/fdialog.cpp b/src/fdialog.cpp
index 0e131c53..d87708cb 100644
--- a/src/fdialog.cpp
+++ b/src/fdialog.cpp
@@ -873,7 +873,8 @@ void FDialog::initMoveSizeMenuItem (FMenu* menu)
   move_size_item->addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &FDialog::cb_move)
+    this,
+    &FDialog::cb_move
   );
 }
 
@@ -896,7 +897,8 @@ void FDialog::initZoomMenuItem (FMenu* menu)
   zoom_item->addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &FDialog::cb_zoom)
+    this,
+    &FDialog::cb_zoom
   );
 }
 
@@ -918,7 +920,8 @@ void FDialog::initCloseMenuItem (FMenu* menu)
   close_item->addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &FDialog::cb_close)
+    this,
+    &FDialog::cb_close
   );
 }
 
@@ -1632,7 +1635,7 @@ void FDialog::delDialog (const FWidget* obj)
 }
 
 //----------------------------------------------------------------------
-void FDialog::cb_move (const FWidget*, const FDataPtr)
+void FDialog::cb_move()
 {
   if ( isZoomed() )
     return;
@@ -1683,7 +1686,7 @@ void FDialog::cb_move (const FWidget*, const FDataPtr)
 }
 
 //----------------------------------------------------------------------
-void FDialog::cb_zoom (const FWidget*, const FDataPtr)
+void FDialog::cb_zoom()
 {
   dialog_menu->unselectItem();
   dialog_menu->hide();
@@ -1694,7 +1697,7 @@ void FDialog::cb_zoom (const FWidget*, const FDataPtr)
 }
 
 //----------------------------------------------------------------------
-void FDialog::cb_close (const FWidget*, const FDataPtr)
+void FDialog::cb_close()
 {
   dialog_menu->unselectItem();
   dialog_menu->hide();
diff --git a/src/ffiledialog.cpp b/src/ffiledialog.cpp
index 69cbb4d5..7b18e59f 100644
--- a/src/ffiledialog.cpp
+++ b/src/ffiledialog.cpp
@@ -380,37 +380,37 @@ void FFileDialog::initCallbacks()
   filename.addCallback
   (
     "activate",
-    F_METHOD_CALLBACK (this, &FFileDialog::cb_processActivate)
+    this, &FFileDialog::cb_processActivate
   );
 
   filebrowser.addCallback
   (
     "row-changed",
-    F_METHOD_CALLBACK (this, &FFileDialog::cb_processRowChanged)
+    this, &FFileDialog::cb_processRowChanged
   );
 
   filebrowser.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &FFileDialog::cb_processClicked)
+    this, &FFileDialog::cb_processClicked
   );
 
   hidden_check.addCallback
   (
     "toggled",
-    F_METHOD_CALLBACK (this, &FFileDialog::cb_processShowHidden)
+    this, &FFileDialog::cb_processShowHidden
   );
 
   cancel_btn.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &FFileDialog::cb_processCancel)
+    this, &FFileDialog::cb_processCancel
   );
 
   open_btn.addCallback
   (
     "clicked",
-    F_METHOD_CALLBACK (this, &FFileDialog::cb_processOpen)
+    this, &FFileDialog::cb_processOpen
   );
 }
 
@@ -754,7 +754,7 @@ const FString FFileDialog::getHomeDir()
 }
 
 //----------------------------------------------------------------------
-void FFileDialog::cb_processActivate (const FWidget*, const FDataPtr)
+void FFileDialog::cb_processActivate()
 {
   if ( filename.getText().includes('*')
     || filename.getText().includes('?') )
@@ -803,7 +803,7 @@ void FFileDialog::cb_processActivate (const FWidget*, const FDataPtr)
 }
 
 //----------------------------------------------------------------------
-void FFileDialog::cb_processRowChanged (const FWidget*, const FDataPtr)
+void FFileDialog::cb_processRowChanged()
 {
   const std::size_t n = filebrowser.currentItem();
 
@@ -821,7 +821,7 @@ void FFileDialog::cb_processRowChanged (const FWidget*, const FDataPtr)
 }
 
 //----------------------------------------------------------------------
-void FFileDialog::cb_processClicked (const FWidget*, const FDataPtr)
+void FFileDialog::cb_processClicked()
 {
   const uLong n = uLong(filebrowser.currentItem() - 1);
 
@@ -832,19 +832,19 @@ void FFileDialog::cb_processClicked (const FWidget*, const FDataPtr)
 }
 
 //----------------------------------------------------------------------
-void FFileDialog::cb_processCancel (const FWidget*, const FDataPtr)
+void FFileDialog::cb_processCancel()
 {
   done (FDialog::Reject);
 }
 
 //----------------------------------------------------------------------
-void FFileDialog::cb_processOpen (const FWidget*, const FDataPtr)
+void FFileDialog::cb_processOpen()
 {
   done (FDialog::Accept);
 }
 
 //----------------------------------------------------------------------
-void FFileDialog::cb_processShowHidden (const FWidget*, const FDataPtr)
+void FFileDialog::cb_processShowHidden()
 {
   setShowHiddenFiles(! show_hidden);
 }
diff --git a/src/flabel.cpp b/src/flabel.cpp
index d388abb1..c9aaa3bc 100644
--- a/src/flabel.cpp
+++ b/src/flabel.cpp
@@ -100,7 +100,7 @@ void FLabel::setAccelWidget (FWidget* widget)
   accel_widget->addCallback
   (
     "destroy",
-    F_METHOD_CALLBACK (this, &FLabel::cb_accelWidgetDestroyed)
+    this, &FLabel::cb_accelWidgetDestroyed
   );
 }
 
@@ -244,7 +244,7 @@ void FLabel::onAccel (FAccelEvent* ev)
 }
 
 //----------------------------------------------------------------------
-void FLabel::cb_accelWidgetDestroyed (const FWidget*, const FDataPtr)
+void FLabel::cb_accelWidgetDestroyed()
 {
   accel_widget = nullptr;
   delAccelerator();
@@ -256,7 +256,7 @@ void FLabel::cb_accelWidgetDestroyed (const FWidget*, const FDataPtr)
 void FLabel::init()
 {
   unsetFocusable();
-  useParentWidgetColor();
+  resetColors();
 }
 
 //----------------------------------------------------------------------
@@ -300,8 +300,6 @@ void FLabel::draw()
   if ( text.isEmpty() )
     return;
 
-
-
   if ( FTerm::isMonochron() )
   {
     setReverse(true);
diff --git a/src/fmenu.cpp b/src/fmenu.cpp
index 6f467921..c249f008 100644
--- a/src/fmenu.cpp
+++ b/src/fmenu.cpp
@@ -327,26 +327,21 @@ void FMenu::onMouseMove (FMouseEvent* ev)
 }
 
 //----------------------------------------------------------------------
-void FMenu::cb_menuitemEnabled (const FWidget*, const FDataPtr)
+void FMenu::cb_menuitemEnabled()
 {
   setEnable();
 }
 
 //----------------------------------------------------------------------
-void FMenu::cb_menuitemDisabled (const FWidget*, const FDataPtr)
+void FMenu::cb_menuitemDisabled()
 {
   setDisable();
 }
 
 //----------------------------------------------------------------------
-void FMenu::cb_menuitemToggled (FWidget* widget, const FDataPtr) const
+void FMenu::cb_menuitemToggled (FMenuItem* m_item) const
 {
-  const auto& m_item = static_cast<FMenuItem*>(widget);
-
-  if ( ! has_checkable_items )
-    return;
-
-  if ( ! m_item->isChecked() )
+  if ( ! (has_checkable_items && m_item && m_item->isChecked()) )
     return;
 
   auto list = getItemList();
@@ -497,13 +492,13 @@ void FMenu::initCallbacks()
   menuitem.addCallback
   (
     "enable",
-    F_METHOD_CALLBACK (this, &FMenu::cb_menuitemEnabled)
+    this, &FMenu::cb_menuitemEnabled
   );
 
   menuitem.addCallback
   (
     "disable",
-    F_METHOD_CALLBACK (this, &FMenu::cb_menuitemEnabled)
+    this, &FMenu::cb_menuitemDisabled
   );
 }
 
diff --git a/src/fmenubar.cpp b/src/fmenubar.cpp
index 3428425d..ac6bc01d 100644
--- a/src/fmenubar.cpp
+++ b/src/fmenubar.cpp
@@ -228,16 +228,14 @@ void FMenuBar::onAccel (FAccelEvent* ev)
 }
 
 //----------------------------------------------------------------------
-void FMenuBar::cb_itemDeactivated (FWidget* widget, const FDataPtr) const
+void FMenuBar::cb_itemDeactivated (FMenuItem* menuitem) const
 {
-  auto menuitem = static_cast<FMenuItem*>(widget);
+  if ( ! menuitem->hasMenu() )
+    return;
 
-  if ( menuitem->hasMenu() )
-  {
-    auto menu = menuitem->getMenu();
-    menu->hide();
-    menu->hideSubMenus();
-  }
+  auto menu = menuitem->getMenu();
+  menu->hide();
+  menu->hideSubMenus();
 }
 
 
diff --git a/src/fmenuitem.cpp b/src/fmenuitem.cpp
index 3679fe33..c02e3543 100644
--- a/src/fmenuitem.cpp
+++ b/src/fmenuitem.cpp
@@ -546,7 +546,8 @@ void FMenuItem::init()
     addCallback  // for this element
     (
       "deactivate",
-      F_METHOD_CALLBACK (menubar_ptr, &FMenuBar::cb_itemDeactivated)
+      std::move(menubar_ptr), &FMenuBar::cb_itemDeactivated,
+      this
     );
   }
   else if ( isMenu(parent) )  // Parent is menu
@@ -628,14 +629,15 @@ void FMenuItem::createDialogList (FMenu* winmenu) const
         win_item->addCallback
         (
           "clicked",
-          F_METHOD_CALLBACK (win_item, &FMenuItem::cb_switchToDialog),
-          static_cast<FDataPtr>(win)
+          std::move(win_item), &FMenuItem::cb_switchToDialog,
+          win
         );
 
         win->addCallback
         (
           "destroy",
-          F_METHOD_CALLBACK (win_item, &FMenuItem::cb_destroyDialog)
+          std::move(win_item), &FMenuItem::cb_destroyDialog,
+          win
         );
 
         win_item->associated_window = win;
@@ -695,28 +697,25 @@ void FMenuItem::passMouseEvent ( T widget, const FMouseEvent* ev
 }
 
 //----------------------------------------------------------------------
-void FMenuItem::cb_switchToDialog (const FWidget*, FDataPtr data) const
+void FMenuItem::cb_switchToDialog (FDialog* win) const
 {
-  auto win = static_cast<FDialog*>(data);
+  if ( ! win )
+    return;
 
-  if ( win )
-  {
-    auto focus = getFocusWidget();
-    FAccelEvent a_ev (fc::Accelerator_Event, focus);
-    FApplication::sendEvent (win, &a_ev);
-  }
+  auto focus = getFocusWidget();
+  FAccelEvent a_ev (fc::Accelerator_Event, focus);
+  FApplication::sendEvent (win, &a_ev);
 }
 
 //----------------------------------------------------------------------
-void FMenuItem::cb_destroyDialog (FWidget* widget, const FDataPtr)
+void FMenuItem::cb_destroyDialog (FDialog* win)
 {
-  auto win = static_cast<FDialog*>(widget);
   const auto& fapp = FApplication::getApplicationObject();
 
   if ( win && fapp )
   {
     delAccelerator(win);
-    delCallback(win);
+    delCallback(std::move(win));
     associated_window = nullptr;
   }
 }
diff --git a/src/fmessagebox.cpp b/src/fmessagebox.cpp
index 269be13e..6896ced0 100644
--- a/src/fmessagebox.cpp
+++ b/src/fmessagebox.cpp
@@ -193,10 +193,9 @@ void FMessageBox::adjustSize()
 }
 
 //----------------------------------------------------------------------
-void FMessageBox::cb_processClick (const FWidget*, FDataPtr data)
+void FMessageBox::cb_processClick (int reply)
 {
-  const int reply = *(static_cast<int*>(data));
-  done (reply);
+  done(reply);
 }
 
 
@@ -281,8 +280,8 @@ inline void FMessageBox::initCallbacks()
     button[0]->addCallback
     (
       "clicked",
-      F_METHOD_CALLBACK (this, &FMessageBox::cb_processClick),
-      static_cast<FDataPtr>(&button_digit[0])
+      this, &FMessageBox::cb_processClick,
+      button_digit[0]
     );
   }
 
@@ -291,8 +290,8 @@ inline void FMessageBox::initCallbacks()
     button[1]->addCallback
     (
       "clicked",
-      F_METHOD_CALLBACK (this, &FMessageBox::cb_processClick),
-      static_cast<FDataPtr>(&button_digit[1])
+      this, &FMessageBox::cb_processClick,
+      button_digit[1]
     );
   }
 
@@ -301,8 +300,8 @@ inline void FMessageBox::initCallbacks()
     button[2]->addCallback
     (
       "clicked",
-      F_METHOD_CALLBACK (this, &FMessageBox::cb_processClick),
-      static_cast<FDataPtr>(&button_digit[2])
+      this, &FMessageBox::cb_processClick,
+      button_digit[2]
     );
   }
 }
diff --git a/src/fradiomenuitem.cpp b/src/fradiomenuitem.cpp
index 48af6014..a2c327e4 100644
--- a/src/fradiomenuitem.cpp
+++ b/src/fradiomenuitem.cpp
@@ -70,7 +70,8 @@ void FRadioMenuItem::init()
     addCallback  // for this element
     (
       "toggled",
-      F_METHOD_CALLBACK (menu_ptr, &FMenu::cb_menuitemToggled)
+      std::move(menu_ptr), &FMenu::cb_menuitemToggled,
+      this
     );
   }
 }
diff --git a/src/fspinbox.cpp b/src/fspinbox.cpp
index ec6fa2b3..6d540e59 100644
--- a/src/fspinbox.cpp
+++ b/src/fspinbox.cpp
@@ -319,12 +319,13 @@ void FSpinBox::init()
   input_field.addCallback
   (
     "activate",
-    F_METHOD_CALLBACK (this, &FSpinBox::cb_inputFieldActivate)
+    this, &FSpinBox::cb_inputFieldActivate
   );
   input_field.addCallback
   (
     "changed",
-    F_METHOD_CALLBACK (this, &FSpinBox::cb_inputFieldChange)
+    this, &FSpinBox::cb_inputFieldChange,
+    std::cref(input_field)
   );
 }
 
@@ -428,23 +429,21 @@ void FSpinBox::forceFocus()
 }
 
 //----------------------------------------------------------------------
-void FSpinBox::cb_inputFieldActivate (const finalcut::FWidget*, const FDataPtr)
+void FSpinBox::cb_inputFieldActivate()
 {
   processActivate();
 }
 
 //----------------------------------------------------------------------
-void FSpinBox::cb_inputFieldChange (finalcut::FWidget* w, const FDataPtr)
+void FSpinBox::cb_inputFieldChange (const FLineEdit& lineedit)
 {
-  const auto& lineedit = static_cast<FLineEdit*>(w);
-
-  if ( lineedit->getText().isEmpty() )
+  if ( lineedit.getText().isEmpty() )
     value = 0;
   else
   {
     std::wregex regex(L"[-]?[[:xdigit:]]+");
     std::wsmatch match;
-    std::wstring text = lineedit->getText().wc_str();
+    std::wstring text = lineedit.getText().wc_str();
 
     if ( std::regex_search(text, match, regex) )
     {
diff --git a/src/fstatusbar.cpp b/src/fstatusbar.cpp
index 806ce8be..0dab686f 100644
--- a/src/fstatusbar.cpp
+++ b/src/fstatusbar.cpp
@@ -273,7 +273,9 @@ void FStatusBar::insert (FStatusKey* skey)
   skey->addCallback
   (
     "activate",
-    F_METHOD_CALLBACK (this, &FStatusBar::cb_statuskey_activated)
+    this,
+    &FStatusBar::cb_statuskey_activated,
+    skey
   );
 }
 
@@ -486,11 +488,13 @@ void FStatusBar::onMouseMove (FMouseEvent* ev)
 }
 
 //----------------------------------------------------------------------
-void FStatusBar::cb_statuskey_activated (FWidget* widget, const FDataPtr)
+void FStatusBar::cb_statuskey_activated (FStatusKey* statuskey)
 {
+  if ( ! statuskey )
+    return;
+
   if ( ! key_list.empty() )
   {
-    const auto& statuskey = static_cast<FStatusKey*>(widget);
     auto iter = key_list.begin();
     const auto& last = key_list.end();
 
diff --git a/src/fvterm.cpp b/src/fvterm.cpp
index 76f9eebf..41255d54 100644
--- a/src/fvterm.cpp
+++ b/src/fvterm.cpp
@@ -2018,6 +2018,8 @@ void FVTerm::finish()
 
   if ( fterm )
     delete fterm;
+
+  init_object = nullptr;
 }
 
 //----------------------------------------------------------------------
@@ -2359,7 +2361,7 @@ bool FVTerm::skipUnchangedCharacters (uInt& x, uInt xmax, uInt y) const
 
 //----------------------------------------------------------------------
 void FVTerm::printRange ( uInt xmin, uInt xmax, uInt y
-                        , bool draw_trailing_ws )
+                        , bool draw_trailing_ws ) const
 {
   for (uInt x = xmin; x <= xmax; x++)
   {
diff --git a/src/fwidget.cpp b/src/fwidget.cpp
index 700e8f1d..68e4d246 100644
--- a/src/fwidget.cpp
+++ b/src/fwidget.cpp
@@ -101,7 +101,7 @@ FWidget::FWidget (FWidget* parent)
 FWidget::~FWidget()  // destructor
 {
   processDestroy();
-  delAllCallbacks();
+  delCallback();
   auto app_object = FApplication::getApplicationObject();
   app_object->removeQueuedEvent(this);
 
@@ -832,94 +832,6 @@ bool FWidget::close()
     return false;
 }
 
-//----------------------------------------------------------------------
-void FWidget::addCallback ( const FString& cb_signal
-                          , const FCallback& cb_function
-                          , FDataPtr data )
-{
-  // Add a (normal) function pointer as callback
-
-  FCallbackData obj{ cb_signal, nullptr, cb_function, data };
-  callback_objects.push_back(obj);
-}
-
-//----------------------------------------------------------------------
-void FWidget::addCallback ( const FString& cb_signal
-                          , FWidget*  cb_instance
-                          , const FCallback& cb_function
-                          , FDataPtr data )
-{
-  // Add a member function pointer as callback
-
-  FCallbackData obj{ cb_signal, cb_instance, cb_function, data };
-  callback_objects.push_back(obj);
-}
-
-//----------------------------------------------------------------------
-void FWidget::delCallback (const FCallback& cb_function)
-{
-  // Deletes entries with cb_function form the callback list
-
-  if ( callback_objects.empty() )
-    return;
-
-  auto iter = callback_objects.begin();
-
-  while ( iter != callback_objects.end() )
-  {
-    if ( getCallbackPtr(iter->cb_function) == getCallbackPtr(cb_function) )
-      iter = callback_objects.erase(iter);
-    else
-      ++iter;
-  }
-}
-
-//----------------------------------------------------------------------
-void FWidget::delCallback (const FWidget* cb_instance)
-{
-  // Deletes entries with cb_instance from the callback list
-
-  if ( callback_objects.empty() )
-    return;
-
-  auto iter = callback_objects.begin();
-
-  while ( iter != callback_objects.end() )
-  {
-    if ( iter->cb_instance == cb_instance )
-      iter = callback_objects.erase(iter);
-    else
-      ++iter;
-  }
-}
-
-//----------------------------------------------------------------------
-void FWidget::delAllCallbacks()
-{
-  // Delete all callbacks from this widget
-
-  callback_objects.clear();  // function pointer
-}
-
-//----------------------------------------------------------------------
-void FWidget::emitCallback (const FString& emit_signal)
-{
-  // Initiate callback for the given signal
-
-  if ( callback_objects.empty() )
-    return;
-
-  for (auto&& cback : callback_objects)
-  {
-    if ( cback.cb_signal == emit_signal )
-    {
-      // Calling the stored function pointer
-      auto callback = cback.cb_function;
-      callback (this, cback.data);
-    }
-  }
-}
-
 //----------------------------------------------------------------------
 void FWidget::addAccelerator (FKey key, FWidget* obj)
 {
@@ -1956,17 +1868,6 @@ void FWidget::setWindowFocus (bool enable)
   window->setWindowFocusWidget(this);
 }
 
-//----------------------------------------------------------------------
-FWidget::FCallbackPtr FWidget::getCallbackPtr (const FCallback& cb_function)
-{
-  auto ptr = cb_function.template target<FCallbackPtr>();
-
-  if ( ptr )
-    return *ptr;
-  else
-    return nullptr;
-}
-
 //----------------------------------------------------------------------
 bool FWidget::changeFocus ( FWidget* follower, FWidget* parent
                           , fc::FocusTypes ft )
diff --git a/src/fwidget_functions.cpp b/src/fwidget_functions.cpp
index d3925da3..b8072edb 100644
--- a/src/fwidget_functions.cpp
+++ b/src/fwidget_functions.cpp
@@ -20,6 +20,7 @@
 * <http://www.gnu.org/licenses/>.                                      *
 ***********************************************************************/
 
+#include "final/fapplication.h"
 #include "final/fcolorpair.h"
 #include "final/fstyle.h"
 #include "final/fwidget.h"
@@ -51,6 +52,12 @@ bool isFocusPrevKey (const FKey key)
   return false;
 }
 
+//----------------------------------------------------------------------
+FApplication* getFApplication()
+{
+  return FApplication::getApplicationObject();
+}
+
 //----------------------------------------------------------------------
 FKey getHotkey (const FString& text)
 {
diff --git a/src/include/final/fapplication.h b/src/include/final/fapplication.h
index 6b85dc8b..7c61a8f9 100644
--- a/src/include/final/fapplication.h
+++ b/src/include/final/fapplication.h
@@ -139,7 +139,7 @@ class FApplication : public FWidget
     static void           closeConfirmationDialog (FWidget*, FCloseEvent*);
 
     // Callback method
-    void cb_exitApp (const FWidget*, const FDataPtr);
+    void                  cb_exitApp (FWidget*);
 
   protected:
     virtual void          processExternalUserEvent();
@@ -214,6 +214,13 @@ class FApplication : public FWidget
     static FWidget*       keyboard_widget;
 };
 
+
+// non-member function forward declarations
+// implemented in fwidget_functions.cpp
+//----------------------------------------------------------------------
+FApplication* getFApplication();
+
+
 // FApplication inline functions
 //----------------------------------------------------------------------
 inline const FString FApplication::getClassName() const
@@ -228,8 +235,8 @@ inline char** FApplication::getArgv() const
 { return app_argv; }
 
 //----------------------------------------------------------------------
-inline void FApplication::cb_exitApp (const FWidget*, const FDataPtr)
-{ close(); }
+inline void FApplication::cb_exitApp (FWidget* w)
+{ w->close(); }
 
 }  // namespace finalcut
 
diff --git a/src/include/final/fbuttongroup.h b/src/include/final/fbuttongroup.h
index eb904cd9..878ff340 100644
--- a/src/include/final/fbuttongroup.h
+++ b/src/include/final/fbuttongroup.h
@@ -130,7 +130,7 @@ class FButtonGroup : public FScrollView
     void                directFocus();
 
     // Callback method
-    void                cb_buttonToggled (FWidget*, const FDataPtr) const;
+    void                cb_buttonToggled (FToggleButton*) const;
 
     // Data members
     FString        text{};
diff --git a/src/include/final/fcallback.h b/src/include/final/fcallback.h
new file mode 100644
index 00000000..d6ec1cad
--- /dev/null
+++ b/src/include/final/fcallback.h
@@ -0,0 +1,449 @@
+/***********************************************************************
+* fcallback.h - Implements the callback functionality                  *
+*                                                                      *
+* This file is part of the FINAL CUT widget toolkit                    *
+*                                                                      *
+* Copyright 2020 Markus Gans                                           *
+*                                                                      *
+* FINAL CUT is free software; you can redistribute it and/or modify    *
+* it under the terms of the GNU Lesser General Public License as       *
+* published by the Free Software Foundation; either version 3 of       *
+* the License, or (at your option) any later version.                  *
+*                                                                      *
+* FINAL CUT is distributed in the hope that it will be useful, but     *
+* WITHOUT ANY WARRANTY; without even the implied warranty of           *
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        *
+* GNU Lesser General Public License for more details.                  *
+*                                                                      *
+* You should have received a copy of the GNU Lesser General Public     *
+* License along with this program.  If not, see                        *
+* <http://www.gnu.org/licenses/>.                                      *
+***********************************************************************/
+
+/*  Standalone class
+ *  ════════════════
+ *
+ * ▕▔▔▔▔▔▔▔▔▔▔▔▏1     *▕▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▏
+ * ▕ FCallback ▏- - - -▕ FCallbackData ▏
+ * ▕▁▁▁▁▁▁▁▁▁▁▁▏       ▕▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▏
+ */
+
+#ifndef FCALLBACK_H
+#define FCALLBACK_H
+
+#if !defined (USE_FINAL_H) && !defined (COMPILE_FINAL_CUT)
+  #error "Only <final/final.h> can be included directly."
+#endif
+
+#include "final/fstring.h"
+#include "final/ftypes.h"
+
+
+namespace finalcut
+{
+
+// class forward declaration
+class FWidget;
+
+//----------------------------------------------------------------------
+// struct FCallbackData
+//----------------------------------------------------------------------
+
+struct FCallbackData
+{
+  // Constructor
+  FCallbackData()
+  { }
+
+  FCallbackData (const FString& s, FWidget* i, void* m, const FCall& c)
+    : cb_signal(s)
+    , cb_instance(i)
+    , cb_function_ptr(m)
+    , cb_function(c)
+  { }
+
+  FCallbackData (const FCallbackData& c)  // copy constructor
+    : cb_signal(c.cb_signal)
+    , cb_instance(c.cb_instance)
+    , cb_function_ptr(c.cb_function_ptr)
+    , cb_function(c.cb_function)
+  { }
+
+  FCallbackData (FCallbackData&& c) noexcept  // move constructor
+    : cb_signal(std::move(c.cb_signal))
+    , cb_instance(std::move(c.cb_instance))
+    , cb_function_ptr(std::move(c.cb_function_ptr))
+    , cb_function(std::move(c.cb_function))
+  { }
+
+  // Destructor
+  ~FCallbackData()
+  { }
+
+  // Overloaded operators
+  FCallbackData& operator = (const FCallbackData& c)
+  {
+    cb_signal = c.cb_signal;
+    cb_instance = c.cb_instance;
+    cb_function_ptr = c.cb_function_ptr;
+    cb_function = c.cb_function;
+    return *this;
+  }
+
+  FCallbackData& operator = (FCallbackData&& c) noexcept
+  {
+    cb_signal = std::move(c.cb_signal);
+    cb_instance = std::move(c.cb_instance);
+    cb_function_ptr = std::move(c.cb_function_ptr);
+    cb_function = std::move(c.cb_function);
+    return *this;
+  }
+
+  // Data members
+  FString   cb_signal{};
+  FWidget*  cb_instance{};
+  void*     cb_function_ptr{};
+  FCall     cb_function{};
+};
+
+
+//----------------------------------------------------------------------
+// class FCallback
+//----------------------------------------------------------------------
+
+class FCallback
+{
+  public:
+    // Constructors
+    FCallback();
+
+    // Disable copy constructor
+    FCallback (const FCallback&) = delete;
+
+    // Destructor
+    ~FCallback();
+
+    // Disable copy assignment operator (=)
+    FCallback& operator = (const FCallback&) = delete;
+
+    // Accessors
+    const FString getClassName() const
+    {
+      return "FCallback";
+    }
+
+    std::size_t getCallbackCount()
+    {
+      return callback_objects.size();
+    }
+
+    // Methods
+    template<typename Object
+           , typename Function
+           , typename std::enable_if< ! std::is_member_function_pointer<Object>::value
+                                   && ! std::is_function<typename std::remove_pointer<Object>::type>::value
+                                   && ! std::is_function<Object>::value
+                                   && std::is_pointer<Object>::value
+                                   && std::is_object<Object>::value
+                                   && ! std::is_class<Object>::value
+                                   && std::is_member_function_pointer<Function>::value
+                                   && ! std::is_function<typename std::remove_pointer<Function>::type>::value
+                                   && ! std::is_function<Function>::value
+                                   && ! std::is_pointer<Function>::value
+                                   && std::is_object<Function>::value
+                                   && ! std::is_class<Function>::value
+                                   , std::nullptr_t >::type = nullptr
+           , typename... Args>
+    void addCallback ( const FString& cb_signal
+                     , Object&&       cb_instance
+                     , Function&&     cb_member
+                     , Args&&...      args)
+    {
+      // Add a member function pointer as callback
+
+      Object instance = cb_instance;
+      auto member = reinterpret_cast<void*>(std::addressof(cb_member));
+      auto fn = std::bind ( std::forward<Function>(cb_member)
+                          , std::forward<Object>(cb_instance)
+                          , std::forward<Args>(args)... );
+      FCallbackData obj{ cb_signal, instance, member, fn };
+      callback_objects.push_back(obj);
+    }
+
+    template<typename Object
+           , typename Function
+           , typename std::enable_if< ! std::is_member_function_pointer<Object>::value
+                                   && ! std::is_function<typename std::remove_pointer<Object>::type>::value
+                                   && ! std::is_function<Object>::value
+                                   && std::is_pointer<Object>::value
+                                   && std::is_object<Object>::value
+                                   && ! std::is_class<Object>::value
+                                   && ! std::is_member_function_pointer<Function>::value
+                                   && ! std::is_function<typename std::remove_pointer<Function>::type>::value
+                                   && ! std::is_function<Function>::value
+                                   && ! std::is_pointer<Function>::value
+                                   && std::is_object<Function>::value
+                                   && std::is_class<Function>::value
+                                   , std::nullptr_t >::type = nullptr
+           , typename... Args>
+    void addCallback ( const FString& cb_signal
+                     , Object&&       cb_instance
+                     , Function&&     cb_function
+                     , Args&&...      args)
+    {
+      // Add a function object to an instance as callback
+
+      auto fn = std::bind (std::forward<Function>(cb_function), std::forward<Args>(args)...);
+      FCallbackData obj{ cb_signal, cb_instance, nullptr, fn };
+      callback_objects.push_back(obj);
+    }
+
+    template<typename Function
+           , typename std::enable_if< ! std::is_member_function_pointer<Function>::value
+                                   && ! std::is_function<typename std::remove_pointer<Function>::type>::value
+                                   && ! std::is_function<Function>::value
+                                   && ! std::is_pointer<Function>::value
+                                   && std::is_object<Function>::value
+                                   && std::is_class<Function>::value
+                                   , std::nullptr_t >::type = nullptr
+           , typename... Args>
+    void addCallback ( const FString& cb_signal
+                     , Function&&     cb_function
+                     , Args&&...      args)
+    {
+      // Add a function object as callback
+
+      auto fn = std::bind ( std::forward<Function>(cb_function)
+                          , std::forward<Args>(args)... );
+      FCallbackData obj{ cb_signal, nullptr, nullptr, fn };
+      callback_objects.push_back(obj);
+    }
+
+    template<typename Function
+           , typename std::enable_if< ! std::is_member_function_pointer<Function>::value
+                                   && std::is_function<typename std::remove_pointer<Function>::type>::value
+                                   && std::is_function<Function>::value
+                                   && ! std::is_pointer<Function>::value
+                                   && ! std::is_object<Function>::value
+                                   && ! std::is_class<Function>::value
+                                   , std::nullptr_t >::type = nullptr
+           , typename... Args>
+    void addCallback ( const FString& cb_signal
+                     , Function&      cb_function
+                     , Args&&...      args)
+    {
+      // Add a function as callback
+
+      auto ptr = reinterpret_cast<void*>(&cb_function);
+      auto fn = std::bind ( std::forward<Function>(cb_function)
+                          , std::forward<Args>(args)... );
+      FCallbackData obj{ cb_signal, nullptr, ptr, fn };
+      callback_objects.push_back(obj);;
+    }
+
+    template<typename Function
+           , typename std::enable_if< ! std::is_member_function_pointer<Function>::value
+                                   && std::is_function<typename std::remove_pointer<Function>::type>::value
+                                   && ! std::is_function<Function>::value
+                                   && std::is_pointer<Function>::value
+                                   && std::is_object<Function>::value
+                                   && ! std::is_class<Function>::value
+                                   , std::nullptr_t >::type = nullptr
+               , typename... Args>
+    void addCallback ( const FString& cb_signal
+                     , Function&&     cb_function
+                     , Args&&...      args)
+    {
+      // Add a function pointer as callback
+
+      auto ptr = reinterpret_cast<void*>(cb_function);
+      auto fn = std::bind ( std::forward<Function>(cb_function)
+                          , std::forward<Args>(args)... );
+      FCallbackData obj{ cb_signal, nullptr, ptr, fn };
+      callback_objects.push_back(obj);
+    }
+
+    template<typename Function
+           , typename std::enable_if< ! std::is_member_function_pointer<Function>::value
+                                   && ! std::is_function<typename std::remove_pointer<Function>::type>::value
+                                   && ! std::is_function<Function>::value
+                                   && ! std::is_pointer<Function>::value
+                                   && std::is_object<Function>::value
+                                   && std::is_class<Function>::value
+                                   , std::nullptr_t >::type = nullptr
+           , typename... Args>
+    void addCallback ( const FString& cb_signal
+                     , Function&      cb_function
+                     , Args&&...      args)
+    {
+      // Add a non-union class type as callback
+
+      auto fn = std::bind ( std::forward<Function>(cb_function)
+                          , std::forward<Args>(args)... );
+      FCallbackData obj{ cb_signal, nullptr, nullptr, fn };
+      callback_objects.push_back(obj);
+    }
+
+    template<typename Object
+           , typename std::enable_if< ! std::is_member_function_pointer<Object>::value
+                                   && ! std::is_function<typename std::remove_pointer<Object>::type>::value
+                                   && ! std::is_function<Object>::value
+                                   && std::is_pointer<Object>::value
+                                   && std::is_object<Object>::value
+                                   && ! std::is_class<Object>::value
+                                   , std::nullptr_t >::type = nullptr >
+    void delCallback (Object&& cb_instance)
+    {
+      // Deletes entries with the given instance from the callback list
+
+      if ( callback_objects.empty() )
+        return;
+
+      auto iter = callback_objects.begin();
+
+      while ( iter != callback_objects.end() )
+      {
+        if ( iter->cb_instance == cb_instance )
+          iter = callback_objects.erase(iter);
+        else
+          ++iter;
+      }
+    }
+
+    void delCallback (const FString& cb_signal)
+    {
+      // Deletes entries with the given signal from the callback list
+
+      if ( callback_objects.empty() )
+        return;
+
+      auto iter = callback_objects.begin();
+
+      while ( iter != callback_objects.end() )
+      {
+        if ( iter->cb_signal == cb_signal )
+          iter = callback_objects.erase(iter);
+        else
+          ++iter;
+      }
+    }
+
+    template<typename Object
+           , typename std::enable_if< ! std::is_member_function_pointer<Object>::value
+                                   && ! std::is_function<typename std::remove_pointer<Object>::type>::value
+                                   && ! std::is_function<Object>::value
+                                   && std::is_pointer<Object>::value
+                                   && std::is_object<Object>::value
+                                   && ! std::is_class<Object>::value
+                                   , std::nullptr_t >::type = nullptr >
+    void delCallback (const FString& cb_signal, Object&& cb_instance)
+    {
+      // Deletes entries with the given signal and instance
+      // from the callback list
+
+      if ( callback_objects.empty() )
+        return;
+
+      auto iter = callback_objects.begin();
+
+      while ( iter != callback_objects.end() )
+      {
+        if ( iter->cb_signal == cb_signal
+          && iter->cb_instance == cb_instance )
+          iter = callback_objects.erase(iter);
+        else
+          ++iter;
+      }
+    }
+
+    template<typename FunctionPtr
+           , typename std::enable_if< ! std::is_member_function_pointer<FunctionPtr>::value
+                                   && std::is_function<typename std::remove_pointer<FunctionPtr>::type>::value
+                                   && ! std::is_function<FunctionPtr>::value
+                                   && std::is_pointer<FunctionPtr>::value
+                                   && std::is_object<FunctionPtr>::value
+                                   && ! std::is_class<FunctionPtr>::value
+                                   , std::nullptr_t >::type = nullptr >
+    void delCallback (FunctionPtr&& cb_func_ptr)
+    {
+      // Deletes entries with the given function pointer
+      // from the callback list
+
+      if ( callback_objects.empty() )
+        return;
+
+      auto ptr = reinterpret_cast<void*>(cb_func_ptr);
+      auto iter = callback_objects.begin();
+
+      while ( iter != callback_objects.end() )
+      {
+        if ( iter->cb_function_ptr == ptr )
+          iter = callback_objects.erase(iter);
+        else
+          ++iter;
+      }
+    }
+
+    template<typename Function
+           , typename std::enable_if< ! std::is_member_function_pointer<Function>::value
+                                   && std::is_function<typename std::remove_pointer<Function>::type>::value
+                                   && std::is_function<Function>::value
+                                   && ! std::is_pointer<Function>::value
+                                   && ! std::is_object<Function>::value
+                                   && ! std::is_class<Function>::value
+                                   , std::nullptr_t >::type = nullptr >
+    void delCallback (Function& cb_function)
+    {
+      // Deletes entries with the given function from the callback list
+
+      if ( callback_objects.empty() )
+        return;
+
+      auto ptr = reinterpret_cast<void*>(&cb_function);
+      auto iter = callback_objects.begin();
+
+      while ( iter != callback_objects.end() )
+      {
+        if ( iter->cb_function_ptr == ptr )
+          iter = callback_objects.erase(iter);
+        else
+          ++iter;
+      }
+    }
+
+    void delCallback()
+    {
+      // Delete all callbacks from this widget
+
+      callback_objects.clear();  // function pointer
+    }
+
+
+    void emitCallback (const FString& emit_signal)
+    {
+      // Initiate callback for the given signal
+
+      if ( callback_objects.empty() )
+        return;
+
+      for (auto&& cback : callback_objects)
+      {
+        if ( cback.cb_signal == emit_signal )
+        {
+          // Calling the stored function pointer
+          cback.cb_function();
+        }
+      }
+    }
+
+  private:
+    // Typedefs
+    typedef std::vector<FCallbackData>  FCallbackObjects;
+
+    // Data members
+    FCallbackObjects  callback_objects{};
+};
+
+}  // namespace finalcut
+
+#endif  // FCALLBACK_H
diff --git a/src/include/final/fcombobox.h b/src/include/final/fcombobox.h
index 62e30897..41f71792 100644
--- a/src/include/final/fcombobox.h
+++ b/src/include/final/fcombobox.h
@@ -215,10 +215,10 @@ class FComboBox : public FWidget
     void                processChanged();
 
     // Callback methods
-    void                cb_setInputField (const FWidget*, const FDataPtr);
-    void                cb_closeComboBox (const FWidget*, const FDataPtr);
-    void                cb_inputFieldSwitch (const FWidget*, const FDataPtr);
-    void                cb_inputFieldHandOver (const FWidget*, const FDataPtr);
+    void                cb_setInputField();
+    void                cb_closeComboBox();
+    void                cb_inputFieldSwitch();
+    void                cb_inputFieldHandOver();
 
     // Data members
     FLineEdit           input_field{this};
diff --git a/src/include/final/fdialog.h b/src/include/final/fdialog.h
index 3af946f2..6374b082 100644
--- a/src/include/final/fdialog.h
+++ b/src/include/final/fdialog.h
@@ -209,9 +209,9 @@ class FDialog : public FWindow
     static void           delDialog (const FWidget*);
 
     // Callback methods
-    void                  cb_move (const FWidget*, const FDataPtr);
-    void                  cb_zoom (const FWidget*, const FDataPtr);
-    void                  cb_close (const FWidget*, const FDataPtr);
+    void                  cb_move();
+    void                  cb_zoom();
+    void                  cb_close();
 
     // Data members
     FString               tb_text{};  // title bar text
diff --git a/src/include/final/ffiledialog.h b/src/include/final/ffiledialog.h
index 82c48b19..eb4ab939 100644
--- a/src/include/final/ffiledialog.h
+++ b/src/include/final/ffiledialog.h
@@ -206,12 +206,12 @@ class FFileDialog : public FDialog
     static const FString getHomeDir();
 
     // Callback methods
-    void                 cb_processActivate (const FWidget*, const FDataPtr);
-    void                 cb_processRowChanged (const FWidget*, const FDataPtr);
-    void                 cb_processClicked (const FWidget*, const FDataPtr);
-    void                 cb_processCancel (const FWidget*, const FDataPtr);
-    void                 cb_processOpen (const FWidget*, const FDataPtr);
-    void                 cb_processShowHidden (const FWidget*, const FDataPtr);
+    void                 cb_processActivate();
+    void                 cb_processRowChanged();
+    void                 cb_processClicked();
+    void                 cb_processCancel();
+    void                 cb_processOpen();
+    void                 cb_processShowHidden();
 
     // Data members
     static FSystem*  fsystem;
diff --git a/src/include/final/flabel.h b/src/include/final/flabel.h
index c07b36db..d9c82cef 100644
--- a/src/include/final/flabel.h
+++ b/src/include/final/flabel.h
@@ -123,7 +123,7 @@ class FLabel : public FWidget
     void                onAccel (FAccelEvent*) override;
 
     // Callback method
-    void                cb_accelWidgetDestroyed (const FWidget*, const FDataPtr);
+    void                cb_accelWidgetDestroyed();
 
   private:
     // Constants
diff --git a/src/include/final/fmenu.h b/src/include/final/fmenu.h
index 34ec1418..89fce8b8 100644
--- a/src/include/final/fmenu.h
+++ b/src/include/final/fmenu.h
@@ -125,9 +125,9 @@ class FMenu : public FWindow, public FMenuList
     void                onAccel (FAccelEvent*) override;
 
     // Callback method
-    void                cb_menuitemEnabled (const FWidget*, const FDataPtr);
-    void                cb_menuitemDisabled (const FWidget*, const FDataPtr);
-    void                cb_menuitemToggled (FWidget*, const FDataPtr) const;
+    void                cb_menuitemEnabled();
+    void                cb_menuitemDisabled();
+    void                cb_menuitemToggled (FMenuItem*) const;
 
   private:
     // Constants
diff --git a/src/include/final/fmenubar.h b/src/include/final/fmenubar.h
index 6e0cbc73..adcaed0e 100644
--- a/src/include/final/fmenubar.h
+++ b/src/include/final/fmenubar.h
@@ -99,7 +99,7 @@ class FMenuBar : public FWindow, public FMenuList
     void          onAccel (FAccelEvent*) override;
 
     // Callback methods
-    void          cb_itemDeactivated (FWidget*, const FDataPtr) const;
+    void          cb_itemDeactivated (FMenuItem*) const;
 
   private:
     // Constants
diff --git a/src/include/final/fmenuitem.h b/src/include/final/fmenuitem.h
index eaa29dee..0c07bc12 100644
--- a/src/include/final/fmenuitem.h
+++ b/src/include/final/fmenuitem.h
@@ -165,8 +165,8 @@ class FMenuItem : public FWidget
     void                passMouseEvent (T, const FMouseEvent*, fc::events) const;
 
     // Callback methods
-    void                cb_switchToDialog (const FWidget*, FDataPtr) const;
-    void                cb_destroyDialog (FWidget*, const FDataPtr);
+    void                cb_switchToDialog (FDialog*) const;
+    void                cb_destroyDialog (FDialog*);
 
     virtual void        processClicked();
 
diff --git a/src/include/final/fmessagebox.h b/src/include/final/fmessagebox.h
index 67f5692a..dfdfebf6 100644
--- a/src/include/final/fmessagebox.h
+++ b/src/include/final/fmessagebox.h
@@ -134,7 +134,7 @@ class FMessageBox : public FDialog
     void                adjustSize() override;
 
     // Callback method
-    void                cb_processClick (const FWidget*, FDataPtr);
+    void                cb_processClick (int);
 
   private:
     // Methods
diff --git a/src/include/final/fscrollbar.h b/src/include/final/fscrollbar.h
index cb24a08c..83cb486e 100644
--- a/src/include/final/fscrollbar.h
+++ b/src/include/final/fscrollbar.h
@@ -196,7 +196,7 @@ void initScrollbar ( FScrollbarPtr& bar
   bar->addCallback
   (
     "change-value",
-    std::bind(cb_handler, cb_instance, _1, _2)
+    std::bind(cb_handler, cb_instance, bar.get(), nullptr)
   );
 }
 
diff --git a/src/include/final/fspinbox.h b/src/include/final/fspinbox.h
index 422c986c..cc48aea7 100644
--- a/src/include/final/fspinbox.h
+++ b/src/include/final/fspinbox.h
@@ -140,8 +140,8 @@ class FSpinBox : public FWidget
     void                forceFocus();
 
     // Callback methods
-    void                cb_inputFieldActivate (const finalcut::FWidget*, const FDataPtr);
-    void                cb_inputFieldChange (finalcut::FWidget*, const FDataPtr);
+    void                cb_inputFieldActivate();
+    void                cb_inputFieldChange (const FLineEdit&);
 
     // Data members
     FLineEdit           input_field{this};
diff --git a/src/include/final/fstatusbar.h b/src/include/final/fstatusbar.h
index 5a661aca..566549c5 100644
--- a/src/include/final/fstatusbar.h
+++ b/src/include/final/fstatusbar.h
@@ -227,7 +227,7 @@ class FStatusBar : public FWindow
     void                onMouseMove (FMouseEvent*) override;
 
     // Callback method
-    void                cb_statuskey_activated (FWidget*, const FDataPtr);
+    void                cb_statuskey_activated (FStatusKey*);
 
   private:
     // Typedef
diff --git a/src/include/final/ftypes.h b/src/include/final/ftypes.h
index 19862ed2..cecfaa8b 100644
--- a/src/include/final/ftypes.h
+++ b/src/include/final/ftypes.h
@@ -31,6 +31,7 @@
 #include <sys/types.h>
 
 #include <cstddef>
+#include <functional>
 #include <limits>
 #include <unordered_map>
 #include <string>
@@ -47,29 +48,29 @@
                             << " in "                          \
                             << __func__ << std::endl;
 
-typedef unsigned char  uChar;
-typedef unsigned short uShort;
-typedef unsigned int   uInt;
-typedef unsigned long  uLong;
-typedef std::uint8_t   uInt8;
-typedef std::uint16_t  uInt16;
-typedef std::uint32_t  uInt32;
-typedef std::uint64_t  uInt64;
+typedef unsigned char         uChar;
+typedef unsigned short        uShort;
+typedef unsigned int          uInt;
+typedef unsigned long         uLong;
+typedef std::uint8_t          uInt8;
+typedef std::uint16_t         uInt16;
+typedef std::uint32_t         uInt32;
+typedef std::uint64_t         uInt64;
 
-typedef signed int     sInt;
-typedef signed long    sLong;
-typedef std::int8_t    sInt8;
-typedef std::int16_t   sInt16;
-typedef std::int32_t   sInt32;
-typedef std::int64_t   sInt64;
+typedef signed int            sInt;
+typedef signed long           sLong;
+typedef std::int8_t           sInt8;
+typedef std::int16_t          sInt16;
+typedef std::int32_t          sInt32;
+typedef std::int64_t          sInt64;
 
-typedef long double    lDouble;
-
-typedef uInt16         FColor;
-typedef uInt16         FAttribute;
-typedef uInt32         FKey;
-typedef void*          FDataPtr;
+typedef long double           lDouble;
 
+typedef uInt16                FColor;
+typedef uInt16                FAttribute;
+typedef uInt32                FKey;
+typedef void*                 FDataPtr;
+typedef std::function<void()> FCall;
 
 namespace finalcut
 {
diff --git a/src/include/final/fvterm.h b/src/include/final/fvterm.h
index a60ee9dc..21a34177 100644
--- a/src/include/final/fvterm.h
+++ b/src/include/final/fvterm.h
@@ -390,7 +390,7 @@ class FVTerm
     static bool           canClearLeadingWS (uInt&, uInt);
     static bool           canClearTrailingWS (uInt&, uInt);
     bool                  skipUnchangedCharacters (uInt&, uInt, uInt) const;
-    void                  printRange (uInt, uInt, uInt, bool);
+    void                  printRange (uInt, uInt, uInt, bool) const;
     void                  replaceNonPrintableFullwidth (uInt, FChar*&) const;
     void                  printCharacter (uInt&, uInt, bool, FChar*&) const;
     void                  printFullWidthCharacter (uInt&, uInt, FChar*&) const;
diff --git a/src/include/final/fwidget.h b/src/include/final/fwidget.h
index bee3e49e..dfb27999 100644
--- a/src/include/final/fwidget.h
+++ b/src/include/final/fwidget.h
@@ -98,6 +98,7 @@
 #include <utility>
 #include <vector>
 
+#include "final/fcallback.h"
 #include "final/fobject.h"
 #include "final/fpoint.h"
 #include "final/frect.h"
@@ -105,16 +106,11 @@
 #include "final/ftypes.h"
 #include "final/fvterm.h"
 
-// Callback macros
-#define F_FUNCTION_CALLBACK(h) \
-    reinterpret_cast<finalcut::FWidget::FCallbackPtr>((h))
-
-#define F_METHOD_CALLBACK(i,h) \
-    reinterpret_cast<finalcut::FWidget*>((i)), \
-    std::bind ( reinterpret_cast<finalcut::FWidget::FMemberCallback>((h)) \
-              , reinterpret_cast<finalcut::FWidget*>((i)) \
-              , std::placeholders::_1 \
-              , std::placeholders::_2 )
+// Old callback macros (deprecated)
+#define F_FUNCTION_CALLBACK(h)  (h), this, nullptr
+#define F_FUNCTION_CALLBACK_DATA(h)  (h), this
+#define F_METHOD_CALLBACK(i,h)  (i), (h), this, nullptr
+#define F_METHOD_CALLBACK_DATA(i,h)  (i), (h), this
 
 namespace finalcut
 {
@@ -147,9 +143,6 @@ class FWidget : public FVTerm, public FObject
     // Typedefs
     typedef std::vector<FWidget*> FWidgetList;
     typedef std::vector<FAccelerator> FAcceleratorList;
-    typedef void (*FCallbackPtr)(FWidget*, FDataPtr);
-    typedef void (FWidget::*FMemberCallback)(FWidget*, FDataPtr);
-    typedef std::function<void(FWidget*, FDataPtr)> FCallback;
     typedef std::shared_ptr<FWidgetColors> FWidgetColorsPtr;
 
     struct FWidgetFlags  // Properties of a widget ⚑
@@ -323,17 +316,11 @@ class FWidget : public FVTerm, public FObject
     int                      numOfFocusableChildren();
     virtual bool             close();
     void                     clearStatusbarMessage();
-    void                     addCallback ( const FString&
-                                         , const FCallback&
-                                         , FDataPtr = nullptr );
-    void                     addCallback ( const FString&
-                                         , FWidget*
-                                         , const FCallback&
-                                         , FDataPtr = nullptr );
-    void                     delCallback (const FCallback&);
-    void                     delCallback (const FWidget*);
-    void                     delAllCallbacks();
-    void                     emitCallback (const FString&);
+    template<typename... Args>
+    void                     addCallback (FString&&, Args&&...);
+    template<typename... Args>
+    void                     delCallback (Args&&...);
+    void                     emitCallback (FString&&);
     void                     addAccelerator (FKey);
     virtual void             addAccelerator (FKey, FWidget*);
     void                     delAccelerator ();
@@ -351,11 +338,6 @@ class FWidget : public FVTerm, public FObject
     static void              quit();
 
   protected:
-    struct FCallbackData;  // forward declaration
-
-    // Typedefs
-    typedef std::vector<FCallbackData> FCallbackObjects;
-
     // Accessor
     FTermArea*               getPrintArea() override;
     static uInt              getModalDialogCounter();
@@ -461,7 +443,6 @@ class FWidget : public FVTerm, public FObject
     void                     KeyDownEvent (FKeyEvent*);
     void                     emitWheelCallback (const FWheelEvent*);
     void                     setWindowFocus (bool);
-    FCallbackPtr             getCallbackPtr (const FCallback&);
     bool                     changeFocus (FWidget*, FWidget*, fc::FocusTypes);
     void                     processDestroy();
     virtual void             draw();
@@ -498,7 +479,7 @@ class FWidget : public FVTerm, public FObject
     FColor                   background_color{fc::Default};
     FString                  statusbar_message{};
     FAcceleratorList         accelerator_list{};
-    FCallbackObjects         callback_objects{};
+    FCallback                callback_impl{};
 
     static FStatusBar*       statusbar;
     static FMenuBar*         menubar;
@@ -532,89 +513,28 @@ class FWidget : public FVTerm, public FObject
     friend void clearFlatBorder (FWidget*);
 };
 
-//----------------------------------------------------------------------
-// struct FWidget::FCallbackData
-//----------------------------------------------------------------------
-struct FWidget::FCallbackData
-{
-  // Constructor
-  FCallbackData()
-  { }
-
-  FCallbackData (const FString& s, FWidget* i, const FCallback& c, FDataPtr d)
-    : cb_signal(s)
-    , cb_instance(i)
-    , cb_function(c)
-    , data(d)
-  { }
-
-  FCallbackData (const FCallbackData& c)  // copy constructor
-    : cb_signal(c.cb_signal)
-    , cb_instance(c.cb_instance)
-    , cb_function(c.cb_function)
-    , data(c.data)
-  { }
-
-  FCallbackData (FCallbackData&& c) noexcept  // move constructor
-    : cb_signal(std::move(c.cb_signal))
-    , cb_instance(std::move(c.cb_instance))
-    , cb_function(std::move(c.cb_function))
-    , data(std::move(c.data))
-  { }
-
-  // Destructor
-  ~FCallbackData()
-  { }
-
-  // Overloaded operators
-  FCallbackData& operator = (const FCallbackData& c)
-  {
-    cb_signal = c.cb_signal;
-    cb_instance = c.cb_instance;
-    cb_function = c.cb_function;
-    data = c.data;
-    return *this;
-  }
-
-  FCallbackData& operator = (FCallbackData&& c) noexcept
-  {
-    cb_signal = std::move(c.cb_signal);
-    cb_instance = std::move(c.cb_instance);
-    cb_function = std::move(c.cb_function);
-    data = std::move(c.data);
-    return *this;
-  }
-
-  // Data members
-  FString   cb_signal{};
-  FWidget*  cb_instance{};
-  FCallback cb_function{};
-  FDataPtr  data{};
-};
-
 
 // non-member function forward declarations
 // implemented in fwidget_functions.cpp
 //----------------------------------------------------------------------
-void        initWidget (FWidget*);
-void        detectTermSize();
-bool        isFocusNextKey (const FKey);
-bool        isFocusPrevKey (const FKey);
-FKey        getHotkey (const FString&);
-std::size_t getHotkeyPos (const FString& src, FString& dest);
-void        setHotkeyViaString (FWidget*, const FString&);
-void        drawShadow (FWidget*);
-void        drawTransparentShadow (FWidget*);
-void        drawBlockShadow (FWidget*);
-void        clearShadow (FWidget*);
-void        drawFlatBorder (FWidget*);
-void        clearFlatBorder (FWidget*);
-void        checkBorder (const FWidget*, FRect&);
-void        drawBorder (FWidget*, const FRect&);
-void        drawListBorder (FWidget*, const FRect&);
-void        drawBox (FWidget*, const FRect&);
-void        drawNewFontBox (FWidget*, const FRect&);
-void        drawNewFontListBox (FWidget*, const FRect&);
+void          detectTermSize();
+bool          isFocusNextKey (const FKey);
+bool          isFocusPrevKey (const FKey);
+FKey          getHotkey (const FString&);
+std::size_t   getHotkeyPos (const FString& src, FString& dest);
+void          setHotkeyViaString (FWidget*, const FString&);
+void          drawShadow (FWidget*);
+void          drawTransparentShadow (FWidget*);
+void          drawBlockShadow (FWidget*);
+void          clearShadow (FWidget*);
+void          drawFlatBorder (FWidget*);
+void          clearFlatBorder (FWidget*);
+void          checkBorder (const FWidget*, FRect&);
+void          drawBorder (FWidget*, const FRect&);
+void          drawListBorder (FWidget*, const FRect&);
+void          drawBox (FWidget*, const FRect&);
+void          drawNewFontBox (FWidget*, const FRect&);
+void          drawNewFontListBox (FWidget*, const FRect&);
 
 
 // FWidget inline functions
@@ -1062,6 +982,27 @@ inline bool FWidget::isPaddingIgnored() const
 inline void FWidget::clearStatusbarMessage()
 { statusbar_message.clear(); }
 
+//----------------------------------------------------------------------
+template<typename... Args>
+inline void FWidget::addCallback (FString&& cb_signal, Args&&... args)
+{
+  callback_impl.addCallback ( std::forward<FString>(cb_signal)
+                            , std::forward<Args>(args)... );
+}
+
+//----------------------------------------------------------------------
+template<typename... Args>
+inline void FWidget::delCallback (Args&&... args)
+{
+  callback_impl.delCallback(std::forward<Args>(args)...);
+}
+
+//----------------------------------------------------------------------
+inline void FWidget::emitCallback (FString&& emit_signal)
+{
+  callback_impl.emitCallback(std::forward<FString>(emit_signal));
+}
+
 //----------------------------------------------------------------------
 inline void FWidget::addAccelerator (FKey key)
 { addAccelerator (key, this); }
diff --git a/test/Makefile.am b/test/Makefile.am
index 6c0f8bfa..f375ea75 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -8,6 +8,7 @@ AM_CPPFLAGS = -I$(top_srcdir)/src/include -Wall -Werror -std=c++11
 
 noinst_PROGRAMS = \
 	fobject_test \
+	fcallback_test \
 	fmouse_test \
 	fkeyboard_test \
 	ftermdata_test \
@@ -28,6 +29,7 @@ noinst_PROGRAMS = \
 	frect_test
 
 fobject_test_SOURCES = fobject-test.cpp
+fcallback_test_SOURCES = fcallback-test.cpp
 fmouse_test_SOURCES = fmouse-test.cpp
 fkeyboard_test_SOURCES = fkeyboard-test.cpp
 ftermdata_test_SOURCES = ftermdata-test.cpp
diff --git a/test/fcallback-test.cpp b/test/fcallback-test.cpp
new file mode 100644
index 00000000..65aef882
--- /dev/null
+++ b/test/fcallback-test.cpp
@@ -0,0 +1,534 @@
+/***********************************************************************
+* callback-test.cpp - FCallback unit tests                             *
+*                                                                      *
+* This file is part of the FINAL CUT widget toolkit                    *
+*                                                                      *
+* Copyright 2020 Markus Gans                                           *
+*                                                                      *
+* FINAL CUT is free software; you can redistribute it and/or modify    *
+* it under the terms of the GNU Lesser General Public License as       *
+* published by the Free Software Foundation; either version 3 of       *
+* the License, or (at your option) any later version.                  *
+*                                                                      *
+* FINAL CUT is distributed in the hope that it will be useful, but     *
+* WITHOUT ANY WARRANTY; without even the implied warranty of           *
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        *
+* GNU Lesser General Public License for more details.                  *
+*                                                                      *
+* You should have received a copy of the GNU Lesser General Public     *
+* License along with this program.  If not, see                        *
+* <http://www.gnu.org/licenses/>.                                      *
+***********************************************************************/
+
+#include <cppunit/BriefTestProgressListener.h>
+#include <cppunit/CompilerOutputter.h>
+#include <cppunit/extensions/HelperMacros.h>
+#include <cppunit/TestFixture.h>
+#include <cppunit/TestResult.h>
+#include <cppunit/TestResultCollector.h>
+#include <cppunit/TestRunner.h>
+
+#include <final/final.h>
+
+//----------------------------------------------------------------------
+// class Widget
+//----------------------------------------------------------------------
+
+class Widget
+{
+  public:
+    template<typename... Args>
+    void addCallback (finalcut::FString&& cb_signal, Args&&... args)
+    {
+      cb.addCallback(std::forward<finalcut::FString>(cb_signal), std::forward<Args>(args)...);
+    }
+
+    template<typename... Args>
+    void delCallback (Args&&... args)
+    {
+      cb.delCallback(std::forward<Args>(args)...);
+    }
+
+    void emitCallback (finalcut::FString&& emit_signal)
+    {
+      cb.emitCallback(std::forward<finalcut::FString>(emit_signal));
+    }
+
+  private:
+    finalcut::FCallback cb{};
+};
+
+
+//----------------------------------------------------------------------
+// class cb_class
+//----------------------------------------------------------------------
+
+class cb_class final : public finalcut::FWidget
+{
+  public:
+    cb_class (int i, finalcut::FWidget* parent)
+      : finalcut::FWidget{parent}
+      , data{i}
+    { }
+
+    void cb_method_ptr (int* value)
+    {
+      (*value)--;
+    }
+
+    void cb_method_ptr_const (int* value) const
+    {
+      *value -= 4;
+    }
+
+    void cb_method_ref (int& value)
+    {
+      value -= data;
+    }
+
+    void cb_method_ref_const (int& value) const
+    {
+      value -= (2 * data);
+    }
+
+  private:
+    int data;
+};
+
+//----------------------------------------------------------------------
+// functions
+//----------------------------------------------------------------------
+void cb_function_ptr (int* value)
+{
+  (*value)++;
+}
+
+//----------------------------------------------------------------------
+void cb_function_ref (int& value)
+{
+  value += 2;
+}
+
+//----------------------------------------------------------------------
+// class FCallbackTest
+//----------------------------------------------------------------------
+
+class FCallbackTest : public CPPUNIT_NS::TestFixture
+{
+  public:
+    FCallbackTest()
+    { }
+
+  protected:
+    void classNameTest();
+    void memberFunctionCallbackTest();
+    void instanceWithFunctionCallbackTest();
+    void functionObjectTest();
+    void functionCallbackTest();
+    void functionPointerCallbackTest();
+    void nonUnionClassCallbackTest();
+    void ownWidgetTest();
+
+  private:
+    // Adds code needed to register the test suite
+    CPPUNIT_TEST_SUITE (FCallbackTest);
+
+    // Add a methods to the test suite
+    CPPUNIT_TEST (classNameTest);
+    CPPUNIT_TEST (memberFunctionCallbackTest);
+    CPPUNIT_TEST (instanceWithFunctionCallbackTest);
+    CPPUNIT_TEST (functionObjectTest);
+    CPPUNIT_TEST (functionCallbackTest);
+    CPPUNIT_TEST (functionPointerCallbackTest);
+    CPPUNIT_TEST (nonUnionClassCallbackTest);
+    CPPUNIT_TEST (ownWidgetTest);
+
+    // End of test suite definition
+    CPPUNIT_TEST_SUITE_END();
+
+    // Data member
+    static finalcut::FWidget root_widget;
+};
+
+// static class attributes
+finalcut::FWidget FCallbackTest::root_widget{nullptr};
+
+//----------------------------------------------------------------------
+void FCallbackTest::classNameTest()
+{
+  const finalcut::FCallback cb;
+  const finalcut::FString& classname = cb.getClassName();
+  CPPUNIT_ASSERT ( classname == "FCallback" );
+}
+
+//----------------------------------------------------------------------
+void FCallbackTest::memberFunctionCallbackTest()
+{
+  finalcut::FCallback cb{};
+  cb_class c{5, &root_widget};
+  int i{75};
+  using Object = decltype(&c);
+  using MemberFunctionPointer = decltype(&cb_class::cb_method_ptr);
+
+  CPPUNIT_ASSERT ( 0 == std::is_member_function_pointer<Object>::value );
+  CPPUNIT_ASSERT ( 0 == std::is_function<typename std::remove_pointer<Object>::type>::value );
+  CPPUNIT_ASSERT ( 0 == std::is_function<Object>::value );
+  CPPUNIT_ASSERT ( 1 == std::is_pointer<Object>::value );
+  CPPUNIT_ASSERT ( 1 == std::is_object<Object>::value );
+  CPPUNIT_ASSERT ( 0 == std::is_class<Object>::value );
+
+  CPPUNIT_ASSERT ( 1 == std::is_member_function_pointer<MemberFunctionPointer>::value );
+  CPPUNIT_ASSERT ( 0 == std::is_function<typename std::remove_pointer<MemberFunctionPointer>::type>::value );
+  CPPUNIT_ASSERT ( 0 == std::is_function<MemberFunctionPointer>::value );
+  CPPUNIT_ASSERT ( 0 == std::is_pointer<MemberFunctionPointer>::value );
+  CPPUNIT_ASSERT ( 1 == std::is_object<MemberFunctionPointer>::value );
+  CPPUNIT_ASSERT ( 0 == std::is_class<MemberFunctionPointer>::value );
+
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 0 );
+
+  cb.addCallback ("clicked", &c, &cb_class::cb_method_ptr, &i);
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 1 );
+
+  cb.addCallback ("activate", &c, &cb_class::cb_method_ptr_const, &i);
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 2 );
+  CPPUNIT_ASSERT ( i == 75 );
+
+  cb.emitCallback ("pressed");
+  CPPUNIT_ASSERT ( i == 75 );
+
+  cb.emitCallback("clicked");
+  CPPUNIT_ASSERT ( i == 74 );
+
+  cb.delCallback ("clicked");
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 1 );
+
+  cb.emitCallback ("clicked");
+  CPPUNIT_ASSERT ( i == 74 );
+
+  cb.emitCallback ("activate");
+  CPPUNIT_ASSERT ( i == 70 );
+
+
+  cb.delCallback ("activate");
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 0 );
+
+  cb.emitCallback ("activate");
+  CPPUNIT_ASSERT ( i == 70 );
+
+  cb.addCallback ("on", &c, &cb_class::cb_method_ref, std::ref(i));
+  cb.addCallback ("on", &c, &cb_class::cb_method_ref_const, std::ref(i));
+  cb.emitCallback ("on");
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 2 );
+  CPPUNIT_ASSERT ( i == 55 );
+
+  cb.delCallback (&c);
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 0 );
+  cb.emitCallback ("on");
+  CPPUNIT_ASSERT ( i == 55 );
+}
+
+//----------------------------------------------------------------------
+void FCallbackTest::instanceWithFunctionCallbackTest()
+{
+  finalcut::FCallback cb{};
+  cb_class c{15, &root_widget};
+  int i{100};
+  auto func1 = std::bind(&cb_class::cb_method_ptr, &c, &i);
+  auto func2 = std::bind(&cb_class::cb_method_ptr_const, &c, &i);
+  auto func3 = std::bind(&cb_class::cb_method_ref, &c, std::ref(i));
+  auto func4 = std::bind(&cb_class::cb_method_ref_const, &c, std::ref(i));
+  auto func5 = std::bind(&cb_class::cb_method_ptr, &c, std::placeholders::_1);
+  auto func6 = std::bind(&cb_class::cb_method_ref, &c, std::placeholders::_1);
+  using Object = decltype(&c);
+  using ClassObject = decltype(func1);
+
+  CPPUNIT_ASSERT ( 0 == std::is_member_function_pointer<Object>::value );
+  CPPUNIT_ASSERT ( 0 == std::is_function<typename std::remove_pointer<Object>::type>::value );
+  CPPUNIT_ASSERT ( 0 == std::is_function<Object>::value );
+  CPPUNIT_ASSERT ( 1 == std::is_pointer<Object>::value );
+  CPPUNIT_ASSERT ( 1 == std::is_object<Object>::value );
+  CPPUNIT_ASSERT ( 0 == std::is_class<Object>::value );
+
+  CPPUNIT_ASSERT ( 0 == std::is_member_function_pointer<ClassObject>::value );
+  CPPUNIT_ASSERT ( 0 == std::is_function<typename std::remove_pointer<ClassObject>::type>::value );
+  CPPUNIT_ASSERT ( 0 == std::is_function<ClassObject>::value );
+  CPPUNIT_ASSERT ( 0 == std::is_pointer<ClassObject>::value );
+  CPPUNIT_ASSERT ( 1 == std::is_object<ClassObject>::value );
+  CPPUNIT_ASSERT ( 1 == std::is_class<ClassObject>::value );
+
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 0 );
+
+  cb.addCallback ("clicked", &c, std::move(func1));
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 1 );
+
+  cb.addCallback ("activate", &c, std::move(func2));
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 2 );
+  CPPUNIT_ASSERT ( i == 100 );
+
+  cb.emitCallback ("pressed");
+  CPPUNIT_ASSERT ( i == 100 );
+
+  cb.emitCallback("clicked");
+  CPPUNIT_ASSERT ( i == 99 );
+
+  cb.delCallback ("clicked");
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 1 );
+
+  cb.emitCallback ("clicked");
+  CPPUNIT_ASSERT ( i == 99 );
+
+  cb.emitCallback ("activate");
+  CPPUNIT_ASSERT ( i == 95 );
+
+  cb.delCallback ("activate");
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 0 );
+
+  cb.emitCallback ("activate");
+  CPPUNIT_ASSERT ( i == 95 );
+
+  cb.addCallback ("on", &c, std::move(func3));
+  cb.addCallback ("on", &c, std::move(func4));
+  cb.emitCallback ("on");
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 2 );
+  CPPUNIT_ASSERT ( i == 50 );
+
+  cb.delCallback (&c);
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 0 );
+  cb.emitCallback ("on");
+  CPPUNIT_ASSERT ( i == 50 );
+
+  cb.addCallback ("enabled", &c, std::move(func5), &i);
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 1 );
+
+  cb.addCallback ("joined", &c, std::move(func6), std::ref(i));
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 2 );
+
+  cb.emitCallback("enabled");
+  CPPUNIT_ASSERT ( i == 49 );
+
+  cb.delCallback ("enabled", &c);
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 1 );
+
+  cb.emitCallback("joined");
+  CPPUNIT_ASSERT ( i == 34 );
+
+  cb.delCallback ("joined", &c);
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 0 );
+}
+
+//----------------------------------------------------------------------
+void FCallbackTest::functionObjectTest()
+{
+  finalcut::FCallback cb{};
+  int i1{2};
+  int i2{3};
+  auto lambda = [] (int& a, const int& b)
+                {
+                  a += b;
+                };
+  using Lambda = decltype(lambda);
+
+  CPPUNIT_ASSERT ( 0 == std::is_member_function_pointer<Lambda>::value );
+  CPPUNIT_ASSERT ( 0 == std::is_function<typename std::remove_pointer<Lambda>::type>::value );
+  CPPUNIT_ASSERT ( 0 == std::is_function<Lambda>::value );
+  CPPUNIT_ASSERT ( 0 == std::is_pointer<Lambda>::value );
+  CPPUNIT_ASSERT ( 1 == std::is_object<Lambda>::value );
+  CPPUNIT_ASSERT ( 1 == std::is_class<Lambda>::value );
+
+  cb.addCallback
+  (
+    "clicked",
+    std::ref(lambda),
+    std::ref(i1),
+    std::cref(i2)
+  );
+  cb.addCallback
+  (
+    "changed",
+    [] (int* a)
+    {
+      (*a)++;
+    },
+    &i2
+  );
+
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 2 );
+  CPPUNIT_ASSERT ( i1 == 2 );
+  cb.emitCallback ("clicked");
+  CPPUNIT_ASSERT ( i1 == 5 );
+
+  i2 = -3;
+  cb.emitCallback ("clicked");
+  CPPUNIT_ASSERT ( i1 == 2 );
+
+  cb.emitCallback ("changed");
+  CPPUNIT_ASSERT ( i2 == -2 );
+
+  cb.emitCallback ("clicked");
+  CPPUNIT_ASSERT ( i1 == 0 );
+
+  cb.delCallback("changed");
+  cb.emitCallback ("changed");
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 1 );
+  CPPUNIT_ASSERT ( i2 == -2 );
+
+  cb.delCallback();
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 0 );
+}
+
+//----------------------------------------------------------------------
+void FCallbackTest::functionCallbackTest()
+{
+  finalcut::FCallback cb{};
+  int i1{22};
+  int i2{11};
+  using Function = decltype(cb_function_ptr);
+
+  CPPUNIT_ASSERT ( 0 == std::is_member_function_pointer<Function>::value );
+  CPPUNIT_ASSERT ( 1 == std::is_function<typename std::remove_pointer<Function>::type>::value );
+  CPPUNIT_ASSERT ( 1 == std::is_function<Function>::value );
+  CPPUNIT_ASSERT ( 0 == std::is_pointer<Function>::value );
+  CPPUNIT_ASSERT ( 0 == std::is_object<Function>::value );
+  CPPUNIT_ASSERT ( 0 == std::is_class<Function>::value );
+
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 0 );
+
+  cb.addCallback ("clicked", cb_function_ptr, &i1);
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 1 );
+  CPPUNIT_ASSERT ( i1 == 22 );
+
+  cb.emitCallback ("clicked");
+  CPPUNIT_ASSERT ( i1 == 23 );
+
+  cb.addCallback ("clicked", cb_function_ref, std::ref(i2));
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 2 );
+  CPPUNIT_ASSERT ( i2 == 11 );
+
+  cb.emitCallback ("clicked");
+  CPPUNIT_ASSERT ( i1 == 24 );
+  CPPUNIT_ASSERT ( i2 == 13 );
+
+  cb.delCallback (&cb_function_ptr);  // Delete via function pointer
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 1 );
+
+  cb.emitCallback ("clicked");
+  CPPUNIT_ASSERT ( i1 == 24 );
+  CPPUNIT_ASSERT ( i2 == 15 );
+
+  cb.delCallback (cb_function_ref);  // Delete via function
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 0 );
+
+  cb.emitCallback ("clicked");
+  CPPUNIT_ASSERT ( i1 == 24 );
+  CPPUNIT_ASSERT ( i2 == 15 );
+}
+
+//----------------------------------------------------------------------
+void FCallbackTest::functionPointerCallbackTest()
+{
+  finalcut::FCallback cb{};
+  int i1{5};
+  int i2{9};
+  using FunctionPointer = decltype(&cb_function_ptr);
+
+  CPPUNIT_ASSERT ( 0 == std::is_member_function_pointer<FunctionPointer>::value );
+  CPPUNIT_ASSERT ( 1 == std::is_function<typename std::remove_pointer<FunctionPointer>::type>::value );
+  CPPUNIT_ASSERT ( 0 == std::is_function<FunctionPointer>::value );
+  CPPUNIT_ASSERT ( 1 == std::is_pointer<FunctionPointer>::value );
+  CPPUNIT_ASSERT ( 1 == std::is_object<FunctionPointer>::value );
+  CPPUNIT_ASSERT ( 0 == std::is_class<FunctionPointer>::value );
+
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 0 );
+
+  cb.addCallback ("clicked", &cb_function_ptr, &i1);
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 1 );
+  CPPUNIT_ASSERT ( i1 == 5 );
+
+  cb.emitCallback ("clicked");
+  CPPUNIT_ASSERT ( i1 == 6 );
+
+  cb.addCallback ("clicked", &cb_function_ref, std::ref(i2));
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 2 );
+  CPPUNIT_ASSERT ( i2 == 9 );
+
+  cb.emitCallback ("clicked");
+  CPPUNIT_ASSERT ( i1 == 7 );
+  CPPUNIT_ASSERT ( i2 == 11 );
+
+  cb.delCallback (&cb_function_ptr);
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 1 );
+
+  cb.emitCallback ("clicked");
+  CPPUNIT_ASSERT ( i1 == 7 );
+  CPPUNIT_ASSERT ( i2 == 13 );
+}
+
+//----------------------------------------------------------------------
+void FCallbackTest::nonUnionClassCallbackTest()
+{
+  finalcut::FCallback cb{};
+  int i{4};
+  auto lambda1 = [] (int* value)
+                 {
+                   *value = *value << 8;
+                 };
+  auto lambda2 = [] (int& value)
+                 {
+                   value = value >> 4;
+                 };
+  using NonUnionClass = decltype(lambda1);
+
+  CPPUNIT_ASSERT ( 0 == std::is_member_function_pointer<NonUnionClass>::value );
+  CPPUNIT_ASSERT ( 0 == std::is_function<typename std::remove_pointer<NonUnionClass>::type>::value );
+  CPPUNIT_ASSERT ( 0 == std::is_function<NonUnionClass>::value );
+  CPPUNIT_ASSERT ( 0 == std::is_pointer<NonUnionClass>::value );
+  CPPUNIT_ASSERT ( 1 == std::is_object<NonUnionClass>::value );
+  CPPUNIT_ASSERT ( 1 == std::is_class<NonUnionClass>::value );
+
+  cb.addCallback ("toggled", lambda1, &i);
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 1 );
+  CPPUNIT_ASSERT ( i == 4 );
+
+  cb.emitCallback ("toggled");
+  CPPUNIT_ASSERT ( i == 1024 );
+
+  cb.addCallback ("row-selected", lambda2, std::ref(i));
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 2 );
+  CPPUNIT_ASSERT ( i == 1024 );
+
+  cb.emitCallback ("row-selected");
+  CPPUNIT_ASSERT ( i == 64 );
+
+  cb.delCallback();
+  CPPUNIT_ASSERT ( cb.getCallbackCount() == 0 );
+}
+
+void FCallbackTest::ownWidgetTest()
+{
+  Widget w;
+  int value = 3141593;
+  int* i = &value;
+  w.addCallback("focus-in", cb_function_ptr, i);
+  CPPUNIT_ASSERT ( value == 3141593 );
+
+  w.emitCallback("focus-in");
+  CPPUNIT_ASSERT ( value == 3141594 );
+
+  w.emitCallback("focus-in");
+  CPPUNIT_ASSERT ( value == 3141595 );
+
+  w.emitCallback("focus-in");
+  CPPUNIT_ASSERT ( value == 3141596 );
+
+  w.delCallback();
+
+  w.emitCallback("focus-in");
+  CPPUNIT_ASSERT ( value != 3141597 );
+  CPPUNIT_ASSERT ( value == 3141596 );
+}
+
+// Put the test suite in the registry
+CPPUNIT_TEST_SUITE_REGISTRATION (FCallbackTest);
+
+// The general unit test main part
+#include <main-test.inc>