Why does my adorner not re-render when the element it's applied to changes?

Question

In a UI I\'m building, I want to adorn a panel whenever one of the controls in the panel has the focus. So I handle the IsKeyboardFocusWithinChanged event, and add

Answer 1

You need to invoke the dispatcher on the panel. Add a handler to the TextBox SizeChanged event:

    private void myTextBox_SizeChanged(object sender, SizeChangedEventArgs e)
    {
        panel.Dispatcher.Invoke((Action)(() => 
        {
            if (panel.IsKeyboardFocusWithin)
            {
                // remove and add adorner to reset
                myAdornerLayer.Remove(myAdorner);
                myAdornerLayer.Add(myAdorner);
            }
        }), DispatcherPriority.Render, null);
    }

This basically comes from this post: http://geekswithblogs.net/NewThingsILearned/archive/2008/08/25/refresh--update-wpf-controls.aspx