--- src/gui/kernel/orig.qwidget_mac.mm	2014-09-26 19:23:04.000000000 +0200
+++ src/gui/kernel/qwidget_mac.mm	2014-09-26 19:36:32.000000000 +0200
@@ -4582,7 +4582,7 @@
         w = qBound(extra->minw, w, extra->maxw);
         h = qBound(extra->minh, h, extra->maxh);
     }
-    const bool isResize = (olds != QSize(w, h));
+    bool isResize = (olds != QSize(w, h));
 
     if (!realWindow && !isResize && QPoint(x, y) == oldp)
         return;
@@ -4619,8 +4619,10 @@
 
         setWSGeometry(false, oldRect);
 
-        if (isResize && QApplicationPrivate::graphicsSystem())
+        if (isResize && q->parentWidget() && QApplicationPrivate::graphicsSystem())
             invalidateBuffer_resizeHelper(oldp, olds);
+        else
+            isResize = false;
     }
 
     if(isMove || isResize) {