diff --git a/lcl/controls.pp b/lcl/controls.pp
index 5b7ba04d8c..526c0186a2 100644
--- a/lcl/controls.pp
+++ b/lcl/controls.pp
@@ -1023,6 +1023,7 @@ type
     Procedure CMDrag(var Message : TCMDrag); message CM_DRAG;
     procedure CMShowingChanged(var Message: TLMessage); message CM_SHOWINGCHANGED;
     procedure CMVisibleChanged(var TheMessage: TLMessage); message CM_VISIBLECHANGED;
+    function  ContainsControl(Control: TControl): Boolean;
     procedure ControlsAligned; virtual;
     procedure DoSendBoundsToInterface; virtual;
     procedure RealizeBounds; virtual;
@@ -1852,6 +1853,9 @@ end.
 { =============================================================================
 
   $Log$
+  Revision 1.160  2003/12/23 16:50:45  micha
+  fix defocus control when destroying it
+
   Revision 1.159  2003/12/14 19:18:03  micha
   hint fixes: parentfont, font itself, showing/hiding + more
 
diff --git a/lcl/forms.pp b/lcl/forms.pp
index ecd825dcdf..20a04fbe51 100644
--- a/lcl/forms.pp
+++ b/lcl/forms.pp
@@ -431,6 +431,7 @@ type
     procedure ShowOnTop;
     function WantChildKey(Child : TControl;
                           var Message : TLMessage): Boolean; virtual;
+    procedure DefocusControl(Control: TWinControl; Removing: Boolean);
     procedure SetFocus; override;
     function SetFocusedControl(Control: TWinControl): Boolean ; Virtual;
     procedure FocusControl(WinControl: TWinControl);
diff --git a/lcl/include/customform.inc b/lcl/include/customform.inc
index 7fbe41debb..5379160520 100644
--- a/lcl/include/customform.inc
+++ b/lcl/include/customform.inc
@@ -457,6 +457,20 @@ begin
   inherited WMSize(Message);
 End;
 
+{------------------------------------------------------------------------------
+  Method: TCustomForm.DefocusControl
+  Params:   Control: the control which is to be defocused
+            Removing: is it to be defocused because it is being removed?
+  Returns:  nothing
+
+  Updates ActiveControl if it is to be defocused
+ ------------------------------------------------------------------------------}
+procedure TCustomForm.DefocusControl(Control: TWinControl; Removing: Boolean);
+begin
+  if Control.ContainsControl(FActiveControl) then
+    ActiveControl := nil;
+end;
+
 {------------------------------------------------------------------------------
   Method: TCustomForm.DoCreate
   Params:   none
@@ -1453,6 +1467,9 @@ end;
 { =============================================================================
 
   $Log$
+  Revision 1.122  2003/12/23 16:50:45  micha
+  fix defocus control when destroying it
+
   Revision 1.121  2003/12/18 08:50:13  micha
   attachmenutowindow cleanup
 
diff --git a/lcl/include/wincontrol.inc b/lcl/include/wincontrol.inc
index 5500a1da04..78554ddf3c 100644
--- a/lcl/include/wincontrol.inc
+++ b/lcl/include/wincontrol.inc
@@ -2045,7 +2045,7 @@ var
   Form: TCustomForm;
 begin
   Form := GetParentForm(Self);
-  if Form <> nil then ;//Form.DefocusControl(Self, Removing);
+  if Form <> nil then Form.DefocusControl(Self, Removing);
 end;
 
 {------------------------------------------------------------------------------}
@@ -2155,6 +2155,19 @@ begin
   end;
 End;
 
+{------------------------------------------------------------------------------
+  Method: TWinControl.ContainsControl
+  Params:  Control: the control to be checked
+  Returns: Self is a (super)parent of Control
+
+  Checks if Control is a child of Self
+ ------------------------------------------------------------------------------}
+function TWinControl.ContainsControl(Control: TControl): Boolean;
+begin
+  while (Control <> nil) and (Control <> Self) do Control := Control.Parent;
+  Result := Control = Self;
+end;
+
 {------------------------------------------------------------------------------
   TWinControl GetBrush
 ------------------------------------------------------------------------------}
@@ -2279,6 +2292,9 @@ var
   Control: TControl;
 begin
   //writeln('[TWinControl.Destroy] A  ',Name,':',ClassName);
+  // prevent parent to try to focus a to be destroyed control
+  if Parent <> nil then
+    RemoveFocus(true);
   if HandleAllocated then
     DestroyHandle;
   //writeln('[TWinControl.Destroy] B  ',Name,':',ClassName);
@@ -3150,6 +3166,9 @@ end;
 { =============================================================================
 
   $Log$
+  Revision 1.182  2003/12/23 16:50:45  micha
+  fix defocus control when destroying it
+
   Revision 1.181  2003/12/14 19:18:04  micha
   hint fixes: parentfont, font itself, showing/hiding + more