diff --git a/lcl/include/wincontrol.inc b/lcl/include/wincontrol.inc
index 98461de687..369f1fe759 100644
--- a/lcl/include/wincontrol.inc
+++ b/lcl/include/wincontrol.inc
@@ -2577,6 +2577,12 @@ var
           '');
       {$ENDIF}
     end;
+    
+    // apply the constraints
+    NewWidth:=ConstraintWidth(NewWidth);
+    NewHeight:=ConstraintHeight(NewHeight);
+    NewRight:=NewLeft+NewWidth;
+    NewBottom:=NewTop+NewHeight;
 
     // set the new bounds
     if (Control.Left <> NewLeft) or (Control.Top <> NewTop)
diff --git a/lcl/interfaces/gtk/gtklclintf.inc b/lcl/interfaces/gtk/gtklclintf.inc
index c300d7d0f7..0c5a351085 100644
--- a/lcl/interfaces/gtk/gtklclintf.inc
+++ b/lcl/interfaces/gtk/gtklclintf.inc
@@ -564,8 +564,8 @@ var
 begin
   Result:=true;
   if Constraints is TSizeConstraints then begin
-    MinWidth := 0;
-    MinHeight := 0;
+    MinWidth := 1;
+    MinHeight := 1;
     MaxWidth:=0;
     MaxHeight:=0;
     SizeConstraints:=TSizeConstraints(Constraints);