diff --git a/lcl/interfaces/win32/win32callback.inc b/lcl/interfaces/win32/win32callback.inc
index 479ce544b5..207ec5de8c 100644
--- a/lcl/interfaces/win32/win32callback.inc
+++ b/lcl/interfaces/win32/win32callback.inc
@@ -73,6 +73,43 @@ Begin
   Assert(False, 'Trace:PropEnumProc - Exit');
 End;
 
+{------------------------------------------------------------------------------
+ Function: OverlayWindowProc
+ Params: Window - The window that receives a message
+         Msg    - The message received
+         WParam - Word parameter
+         LParam - Long-integer parameter
+  Returns: 0 if Msg is handled; non-zero long-integer result otherwise
+
+  Handles messages specifically for the window used by GetDesignerDC
+ ------------------------------------------------------------------------------}
+function OverlayWindowProc(Window: HWnd; Msg: UInt; WParam: Windows.WParam;
+    LParam: Windows.LParam): LResult; stdcall;
+var
+  PS: PAINTSTRUCT;
+  PrevWndProc: Pointer;
+begin
+  case Msg of
+    WM_ERASEBKGND:
+    begin
+      Result := 1;
+    end;
+    WM_PAINT:
+    begin
+      Windows.BeginPaint(Window, @PS);
+      Windows.EndPaint(Window, @PS);
+      Result := 1;
+    end;
+  else
+    // default handling of message
+    PrevWndProc := GetProp(Window, 'DefWndProc');
+    if PrevWndProc = nil then
+      Result := Windows.DefWindowProc(Window, Msg, WParam, LParam)
+    else
+      Result := Windows.CallWindowProc(Windows.WNDPROC(PrevWndProc), Window, Msg, WParam, LParam);
+  end;
+end;
+
 {------------------------------------------------------------------------------
  Function: WindowProc
  Params: Window - The window that receives a message
@@ -733,10 +770,9 @@ Begin
         Unused := WParam;
         WindowPos := PWindowPos(LParam);
       End;
-//      GetClientRect(Window, R);
-//      SendMessage(Window, WM_MOVE, 0, MakeLParam(PWindowPos(LParam)^.x, PWindowPos(LParam)^.y));
-//      SendMessage(Window, WM_SIZE, 0, MakeLParam(R.right-R.left, R.bottom-R.top));
-//      WinProcess:=false;
+      // cross-interface compatible: complete invalidate on resize
+      if (PWindowPos(LParam)^.flags and SWP_NOSIZE) = 0 then
+        Windows.InvalidateRect(Window, nil, true);
     End;
     WM_MEASUREITEM:
     Begin
@@ -938,6 +974,9 @@ end;
 
 {
   $Log$
+  Revision 1.87  2004/01/12 08:20:50  micha
+  implement overlay window for designer
+
   Revision 1.86  2004/01/07 18:05:46  micha
   add TWinControl.DoubleBuffered property which is a hint for the interface to do double-buffering for this control
 
diff --git a/lcl/interfaces/win32/win32winapi.inc b/lcl/interfaces/win32/win32winapi.inc
index 3e39a78c83..13c4aff7b1 100644
--- a/lcl/interfaces/win32/win32winapi.inc
+++ b/lcl/interfaces/win32/win32winapi.inc
@@ -1364,8 +1364,24 @@ begin
 end;
 
 function TWin32Object.GetDesignerDC(WindowHandle: HWND): HDC;
+var
+  OverlayWindow: HWND;
+  ARect: Windows.RECT;
 begin
-  Result := Windows.GetDC(0);
+  OverlayWindow := HWND(Windows.GetProp(WindowHandle, 'Overlay'));
+  if OverlayWindow = HWND(nil) then
+  begin
+    // create 'overlay' window
+    Windows.GetClientRect(WindowHandle, @ARect);
+    OverlayWindow := Windows.CreateWindowEx(WS_EX_TRANSPARENT,
+        'STATIC', '', WS_CHILD or WS_VISIBLE,
+        ARect.Left, ARect.Top, ARect.Right, ARect.Bottom,
+        WindowHandle, HMENU(nil), HInstance, nil);
+    Windows.SetProp(OverlayWindow, 'DefWndProc', Windows.SetWindowLong(
+        OverlayWindow, GWL_WNDPROC, LongInt(@OverlayWindowProc)));
+    Windows.SetProp(WindowHandle, 'Overlay', OverlayWindow);
+  end;
+  Result := Windows.GetDC(OverlayWindow);
 end;
 
 function TWin32Object.GetDeviceSize(DC: HDC; var P: TPoint): Boolean;
@@ -2320,7 +2336,7 @@ End;
 Function TWin32Object.ReleaseDesignerDC(HWnd: HWND; DC: HDC): Integer;
 Begin
   Assert(False, Format('Trace:> [TWin32Object.ReleaseDC] DC:0x%x', [DC]));
-  Result := Windows.ReleaseDC(0, DC);
+  Result := Windows.ReleaseDC(HWnd, DC);
   Assert(False, Format('Trace:< [TWin32Object.ReleaseDC] DC:0x%x', [DC]));
 End;
 
@@ -2887,6 +2903,9 @@ end;
 { =============================================================================
 
   $Log$
+  Revision 1.92  2004/01/12 08:20:50  micha
+  implement overlay window for designer
+
   Revision 1.91  2004/01/03 21:06:06  micha
   - fix win32/checklistbox
   - implement proper lcl to interface move/size notify via setwindowpos