1.add toobar to window controller.
2.delete the original view controller.
3.add new View controller.
4.add container vew to the 'new view controller'.
5.add custom view to the 'new view controller'.
6.put the button on the custom view.
7.connect the window controller to the view controller.
8.add 'vertical split view controller'
9.delete container view's original view controller.
10.connect 'container view' to 'vertical split view contriller'.
11.set auto label.
（个人总结）