code: function(event, g, context) {
      if (context.cancelNextDblclick) {
        context.cancelNextDblclick = false;
        return;
      }
  
      // Give plugins a chance to grab this event.
      var e = {
        canvasx: context.dragEndX,
        canvasy: context.dragEndY,
        cancelable: true,
      };
      if (g.cascadeEvents_('dblclick', e)) {
        return;
      }
  
      if (event.altKey || event.shiftKey) {
        return;
      }
      g.resetZoom();
    }
docs: Disable zooming out if panning.