diff --git a/ChangeLog b/ChangeLog
index e6b04a2d..f755c339 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -7,7 +7,8 @@
 
 2018-11-18  Markus Gans  <guru.mail@muenster.de>
 	* The FListViewItem class now provides checkable list view items
-	* Adding the checklist example to demonstrate the checkable FListViewItems
+	* Adding the checklist example to demonstrate the checkable 
+	  FListViewItems
 	* A checkable FListViewItem now shows the input cursor
 
 2018-11-12  Markus Gans  <guru.mail@muenster.de>
diff --git a/build.sh b/build.sh
index ae0c9e42..f711d2b3 100755
--- a/build.sh
+++ b/build.sh
@@ -43,7 +43,7 @@ fi
 # Build commands
 case "$1" in
   "--release"|"release")
-    if ! ./configure --prefix="$PREFIX" CXXFLAGS="-O3 -fno-rtti"
+    if ! ./configure --prefix="$PREFIX" CXXFLAGS="-O2" # "-O3 -fno-rtti"
     then
       echo "${RED}Configure failed!${NORMAL}" 1>&2
       exit -1
diff --git a/examples/transparent.cpp b/examples/transparent.cpp
index 3672c440..ddc04a55 100644
--- a/examples/transparent.cpp
+++ b/examples/transparent.cpp
@@ -184,9 +184,9 @@ class MainWindow : public finalcut::FDialog
     // Data Members
     finalcut::FString line1;
     finalcut::FString line2;
-    Transparent transpwin;
-    Transparent shadowwin;
-    Transparent ibg;
+    Transparent* transpwin;
+    Transparent* shadowwin;
+    Transparent* ibg;
     finalcut::FStatusBar status_bar;
 };
 #pragma pack(pop)
@@ -196,25 +196,32 @@ MainWindow::MainWindow (finalcut::FWidget* parent)
   : FDialog(parent)
   , line1()
   , line2()
-  , transpwin(this)
-  , shadowwin(this, Transparent::shadow)
-  , ibg(this, Transparent::inherit_background)
+  , transpwin(0)
+  , shadowwin(0)
+  , ibg(0)
   , status_bar(this)
 {
   line1 = "     .-.     .-.     .-.";
   line2 = "`._.'   `._.'   `._.'   ";
 
-  transpwin.setText("transparent");
-  transpwin.setGeometry (6, 3, 29, 12);
-  transpwin.unsetTransparentShadow();
+  // The memory allocation for the following three sub windows occurs
+  // with the operator new. The lifetime of the generated widget
+  // is managed by the parent object (this). The operator delete
+  // is not required in this scope and would result in a double free.
+  transpwin = new Transparent(this);
+  transpwin->setText("transparent");
+  transpwin->setGeometry (6, 3, 29, 12);
+  transpwin->unsetTransparentShadow();
 
-  shadowwin.setText("shadow");
-  shadowwin.setGeometry (46, 11, 29, 12);
-  shadowwin.unsetTransparentShadow();
+  shadowwin = new Transparent(this, Transparent::shadow);
+  shadowwin->setText("shadow");
+  shadowwin->setGeometry (46, 11, 29, 12);
+  shadowwin->unsetTransparentShadow();
 
-  ibg.setText("inherit background");
-  ibg.setGeometry (42, 3, 29, 7);
-  ibg.unsetTransparentShadow();
+  ibg = new Transparent(this, Transparent::inherit_background);
+  ibg->setText("inherit background");
+  ibg->setGeometry (42, 3, 29, 7);
+  ibg->unsetTransparentShadow();
 
   // Statusbar at the bottom
   status_bar.setMessage("Press Q to quit");
diff --git a/src/foptimove.cpp b/src/foptimove.cpp
index 41c236fc..e5928d1a 100644
--- a/src/foptimove.cpp
+++ b/src/foptimove.cpp
@@ -646,11 +646,13 @@ int FOptiMove::repeatedAppend ( const capability& o
     if ( dst )
     {
       dst += dst_len;
+      std::size_t free = BUF_SIZE - dst_len;
 
       while ( count-- > 0 )
       {
-        std::strncpy (dst, o.cap, src_len + 1);
+        std::strncpy (dst, o.cap, free);
         dst += src_len;
+        free -= src_len;
       }
     }
   }
@@ -793,7 +795,7 @@ inline int FOptiMove::horizontalMove (char hmove[], int from_x, int to_x)
     // Move to fixed column position1
     std::strncat ( hmove
                  , tparm(F_column_address.cap, to_x, 0, 0, 0, 0, 0, 0, 0, 0)
-                 , BUF_SIZE - std::strlen(hmove) - 1);
+                 , BUF_SIZE - std::strlen(hmove) - 1 );
     hmove[BUF_SIZE - 1] = '\0';
     htime = F_column_address.duration;
   }
diff --git a/src/fterm.cpp b/src/fterm.cpp
index af1f6205..4b40ce58 100644
--- a/src/fterm.cpp
+++ b/src/fterm.cpp
@@ -63,6 +63,9 @@ FMouseControl*      FTerm::mouse            = 0;
   FTermDebugData* FTerm::debug_data = 0;
 #endif
 
+// function prototypes
+uInt env2uint (const char*);
+
 
 //----------------------------------------------------------------------
 // class FTerm
@@ -487,11 +490,11 @@ void FTerm::detectTermSize()
   {
     term_geometry.setPos (1, 1);
     // Use COLUMNS or fallback to the xterm default width of 80 characters
-    char* Columns = std::getenv("COLUMNS");
-    term_geometry.setWidth(Columns ? std::size_t(std::atoi(Columns)) : 80);
+    uInt Columns = env2uint ("COLUMNS");
+    term_geometry.setWidth( ( Columns == 0) ? 80 : Columns);
     // Use LINES or fallback to the xterm default height of 24 characters
-    char* Lines = std::getenv("LINES");
-    term_geometry.setHeight(Lines ? std::size_t(std::atoi(Lines)) : 24);
+    uInt Lines = env2uint ("LINES");
+    term_geometry.setHeight( ( Lines == 0 ) ? 24 : Lines);
   }
   else
   {
@@ -2072,6 +2075,26 @@ void FTerm::signal_handler (int signum)
                    , strsignal(signum) );
       std::terminate();
   }
+
+}
+
+// FTerm non-member functions
+//----------------------------------------------------------------------
+uInt env2uint (const char* env)
+{
+  FString str(env);
+
+  if ( str.isEmpty() )
+    return 0;
+
+  try
+  {
+    return str.toUInt();
+  }
+  catch (const std::exception& ex)
+  {
+    return 0;
+  }
 }
 
 }  // namespace finalcut
diff --git a/test/ftermdetection-test.cpp b/test/ftermdetection-test.cpp
index 027b586e..2fff2390 100644
--- a/test/ftermdetection-test.cpp
+++ b/test/ftermdetection-test.cpp
@@ -2314,7 +2314,7 @@ void FTermDetectionTest::terminalSimulation (console con)
     {
       len = read (fd_stdin, buffer, sizeof(buffer));
 
-      if ( len != -1 && std::size_t(len) < sizeof(buffer) )
+      if ( len > 0 && std::size_t(len) < sizeof(buffer) )
       {
         buffer[len] = '\0';
         write (fd_master, buffer, len);  // Send data to the master side