protected override void OnPreRender(EventArgs e)
{
// If Show() or Hide() were called during the request, change the visibility now
if(_show.HasValue)
ChangeVisibility(_show.Value);
ResolveControlIDs(_onShown);
ResolveControlIDs(_onHidden);
ResolveControlIDs(_onShowing);
ResolveControlIDs(_onHiding);
base.OnPreRender(e);
}