private void Calendar_SizeChanged(object sender, SizeChangedEventArgs e) { Debug.Assert(sender is Calendar, "The sender should be a Calendar!"); RectangleGeometry rg = new RectangleGeometry(); rg.Rect = new Rect(0, 0, e.NewSize.Width, e.NewSize.Height); if (Root != null) { Root.Clip = rg; } }