public void ShowOverlapLayer(int pos) {
		if (OverlapShow) {
			if ((OverlapFlags == Center && pos != Center) ||
			    (OverlapFlags != Center && pos == Center)) {	
				trace("CMainWin::ShowOverlapLayer 显示在中间，删除所有之前显示的图形");
				Invalidate(Position[OverlapFlags]);
				OverlapFlags = None;
				OverlapBounds.setBounds(0, 0, 0, 0);
			}
		}
		OverlapFlags |= pos;
		OverlapBounds = Position[OverlapFlags];
		OverlapShow = true;
		trace("CMainWin::ShowOverlapLayer Invalidate == " + Position[pos]);
		Invalidate(Position[pos]);
	}