diff --git a/lcl/include/wincontrol.inc b/lcl/include/wincontrol.inc
index aae38d2683..f088908b41 100644
--- a/lcl/include/wincontrol.inc
+++ b/lcl/include/wincontrol.inc
@@ -6820,11 +6820,11 @@ begin
   and (not (wcfClientRectNeedsUpdate in FWinControlFlags)) then
     exit;
 
-  { $IFDEF VerboseAllAutoSize}
+  {$IFDEF VerboseAllAutoSize}
   DebugLn(['TWinControl.WMWindowPosChanged CHANGED BY INTF ',dbgsname(Self),' Message=',NewLeft,',',NewTop,',',NewWidth,'x',NewHeight,
     ' BoundsRealized=',dbgs(FBoundsRealized),
     ' wcfClientRectNeedsUpdate=',wcfClientRectNeedsUpdate in FWinControlFlags]);
-  { $ENDIF}
+  {$ENDIF}
 
   TopParent:=GetTopParent;
   if (TopParent is TWinControl)
@@ -7256,6 +7256,7 @@ begin
       Exclude(FWinControlFlags, wcfCreatingChildHandles);
     end;
 
+    InvalidatePreferredSize;
     if FControls<>nil then
       for i:=0 to FControls.Count-1 do
         TControl(FControls[i]).InvalidatePreferredSize;