page.js

                contentView: OI.MailboxSourceView.design({
                  layerId: 'mailbox-list',
                  classNames: 'mailbox-list'.w(),
                  // delegate: 'OI*mailboxesController',
                  contentValueKey: 'name',
                  contentUnreadCountKey: 'unreadCount',
                  contentBinding: 'OI*mailboxesController.arrangedObjects',
                  selectionBinding: 'OI*mailboxesController.selection',
                  selectOnMouseDown: YES,
                  acceptsFirstResponder: YES,
                  delegate: OI,
                  didBecomeFirstResponder: function() {
                    OI.didBecomeFirstResponder(this) ;
                  },
                  willLoseFirstResponder: function() {
                    OI.willLoseFirstResponder(this) ;
                  },
                  moveLeft: function(sender, evt) {
                    return OI.moveLeft(sender, evt) ;
                  },
                  moveRight: function(sender, evt) {
                    return OI.moveRight(sender, evt) ;
                  },
                  exampleView: SC.ListItemView.design({
                    layoutStyle: function() {
                      var layout = this.layout ;
                      var oldHeight = layout.height ;
                      layout.height = oldHeight - 2 ;
                      var res = sc_super() ;
                      layout.height = oldHeight ;
                      return res ;
                    }.property().cacheable()
                  })
                })
              }),