/// <summary>
/// Invalidates space occupied by this element.
/// This causes repaint of any elements overlapped by elements region
/// </summary>
public void Invalidate()
{
const int SAFE_MARGIN = 2;//repaint a bit more than windows asks
Rectangle rgn = DisplayRegion;
rgn.Inflate(SAFE_MARGIN, SAFE_MARGIN);
m_Host.Invalidate(rgn);
}
