private void __showScrollBar(object obj)
{
_scrollBarVisible = (bool)obj && _viewWidth > 0 && _viewHeight > 0;
if (_vtScrollBar != null)
_vtScrollBar.displayObject.visible = _scrollBarVisible && !_vScrollNone;
if (_hzScrollBar != null)
_hzScrollBar.displayObject.visible = _scrollBarVisible && !_hScrollNone;
}