diff --git a/lcl/include/wincontrol.inc b/lcl/include/wincontrol.inc
index 5ce55594fe..c8915814f8 100644
--- a/lcl/include/wincontrol.inc
+++ b/lcl/include/wincontrol.inc
@@ -3444,6 +3444,8 @@ begin
           Result.Bottom:=FLoadedClientSize.Y;
       end;
     end;
+    Result.Right:=Max(Result.Left,Result.Right);
+    Result.Bottom:=Max(Result.Top,Result.Bottom);
     StoreClientRect(Result);
 
     {r:=inherited GetClientRect;