public virtual void Show(Rectangle screenRect)
{
// Update the screen position
SetBounds(screenRect.X, screenRect.Y,
screenRect.Width, screenRect.Height);
// If we have a shadow then update it now
if (_shadow != null)
_shadow.Show(screenRect);
// Show the window without activating it (i.e. do not take focus)
PI.ShowWindow(this.Handle, PI.SW_SHOWNOACTIVATE);
// Use manager to track mouse/keyboard input and to dismiss the window
VisualPopupManager.Singleton.StartTracking(this);
}