菜单也是用视图层次进行构架的，但你不必自己定义这个架构。

Menus are also structured using a View hierarchy, but you don't define this structure yourself.

youdao

你无法修改最底下那个叫做“背景”的图层。所以选择它，在图层面板上部的选项菜单中复制图层。

You can't fully manipulate the bottom layer called 'Background', so select this layer, go up to the options at the top of the Layers palette and duplicate the layer.

youdao

右击那个图层，从菜单里选择背景图层，点击确定。

Right-click on that layer, select Layer from Background from the menu that appears, and then click OK.

youdao