这种动态效果出现在同时具有左、右导航菜单的网站。

The effect appears in both left - and right-side navigation menus.

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你可以采取在桌面软件上非常常见的弹出框菜单和控件来达到这种效果。

You can do this with pop-up menus and controls, which are very common on desktop software.

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然后，修改工作组列表项锚元素的背景，使效果看上去像是菜单条目前面的符号改变了颜色。

Then, the workgroup list item anchor background is changed so that what looks like the menu item bullet changes color.

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