def queryBuilderWidget( self ):
        """
        Returns the query builder widget instance that this widget is \
        associated with.
        
        :return     <XQueryBuilderWidget>
        """
        from projexui.widgets.xquerybuilderwidget import XQueryBuilderWidget
        
        builder = self.parent()
        while ( builder and not isinstance(builder, XQueryBuilderWidget) ):
            builder = builder.parent()
        
        return builder