title: Scrollbar does not update on changing the scroll value
body: <p>When setting <code>VerticalScroll.Value</code> in a <code>Panel</code> with <code>AutoScroll</code> set to <code>true</code>, the scroll position changes accordingly but the position of the thumb does not. Do I need to update the scrollbar somehow (<code>Invalidate(true)</code> on the panel does not work)? Any ideas?</p>