Update widget.py

Fix #516 test failure

TermTk/TTkWidgets/widget.py

@@ -615,7 +615,6 @@ class TTkWidget(TMouseEvents,TKeyEvents, TDragEvents):
         if self._parent is not None and \
            self._parent.rootLayout() is not None:
             self._parent.rootLayout().removeWidget(self)
-            self._parent.update()
         TTkHelper.removeOverlayAndChild(self)
         self._parent = None
         self.hide()
@@ -779,4 +778,4 @@ class TTkWidget(TMouseEvents,TKeyEvents, TDragEvents):
             self._currentStyle = self._style['disabled']
             self.update()
             return True
-        return False
+        return False