public void WaitforDraw(SystemWindow containingWindow, int maxSeconds = 30)
{
var resetEvent = new AutoResetEvent(false);
EventHandler <DrawEventArgs> afterDraw = (s, e) => resetEvent.Set();
EventHandler <ClosedEventArgs> closed = (s, e) => resetEvent.Set();
containingWindow.AfterDraw += afterDraw;
containingWindow.Closed += closed;
containingWindow.Invalidate();
resetEvent.WaitOne(maxSeconds * 1000);
containingWindow.AfterDraw -= afterDraw;
containingWindow.Closed -= closed;
}