code: function(rect, opt) {
  
          opt = joint.util.defaults(opt || {}, { strict: false });
          rect = new g.Rect(rect);
  
          var views = this.model.getElements().map(this.findViewByModel, this);
          var method = opt.strict ? 'containsRect' : 'intersect';
  
          return views.filter(function(view) {
              return view && rect[method](view.vel.getBBox({ target: this.viewport }));
          }, this);
      }
docs: Find all views in given area