added selection reset for all widgets derived from EditableWidget

src/debugger/gui/DataGridWidget.cxx

@@ -259,6 +259,7 @@ void DataGridWidget::handleMouseDown(int x, int y, MouseButton b, int clickCount
   if (!isEnabled())
     return;
 
+  resetSelection();
   // First check whether the selection changed
   int newSelectedItem;
   newSelectedItem = findItem(x, y);

src/debugger/gui/RomListWidget.cxx

@@ -235,6 +235,7 @@ void RomListWidget::handleMouseDown(int x, int y, MouseButton b, int clickCount)
   if (!isEnabled())
     return;
 
+  resetSelection();
   // Grab right mouse button for context menu, left for selection/edit mode
   if(b == MouseButton::RIGHT)
   {

src/gui/EditableWidget.cxx

@@ -118,12 +118,15 @@ bool EditableWidget::handleKeyDown(StellaKey key, StellaMod mod)
   if(StellaModTest::isAlt(mod))
     return true;
 
+  // Handle Control and Control-Shift keys
   if(StellaModTest::isControl(mod) && handleControlKeys(key, mod))
     return true;
 
+  // Handle Shift keys
   if(StellaModTest::isShift(mod) && handleShiftKeys(key))
     return true;
 
+  // Handle keys without modifiers
   return handleNormalKeys(key);
 }
 

src/gui/EditableWidget.hxx

@@ -110,6 +110,10 @@ class EditableWidget : public Widget, public CommandSender
     bool   _editable{true};
     string _editString;
     int    _caretPos{0};
+    // Size of current selected text
+    //    0 = no selection
+    //   <0 = selected left of caret
+    //   >0 = selected right of caret
     int    _selectSize{0};
 
   protected:

src/gui/ListWidget.cxx

@@ -205,6 +205,7 @@ void ListWidget::handleMouseDown(int x, int y, MouseButton b, int clickCount)
   if (!isEnabled())
     return;
 
+  resetSelection();
   // First check whether the selection changed
   int newSelectedItem;
   newSelectedItem = findItem(x, y);

src/gui/PopUpWidget.cxx

@@ -117,6 +117,7 @@ const Variant& PopUpWidget::getSelectedTag() const
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 void PopUpWidget::handleMouseDown(int x, int y, MouseButton b, int clickCount)
 {
+  resetSelection();
   if(!isEditable() || x > _w - dropDownWidth(_font))
   {
     if(isEnabled() && !myMenu->isVisible())