if (c == null && c.isDisposed())
if (c == null || c.isDisposed())
	private void setSmartButtonVisible(boolean visible) {		if (fSmartActionItem == null)			return;		Control c= getControl();		if (c == null && c.isDisposed())			return;					fSmartActionItem.setVisible(visible);		ToolBarManager tbm= CompareViewerPane.getToolBarManager(c.getParent());		if (tbm != null) {			tbm.update(true);			ToolBar tb= tbm.getControl();			if (!tb.isDisposed())				tb.getParent().layout(true);		}	}