If there are too many operations to display, you can wrap them in a `Dropdown`. By clicking/hovering on the trigger, a dropdown menu should appear, which allows you to choose one option and execute relevant actions.
| overlay | the dropdown menu | [Menu](/components/menu) | - |
| getPopupContainer | to set the container of the dropdown menu. The default is to create a `div` element in `body`, you can reset it to the scrolling area and make a relative reposition. [example](http://codepen.io/anon/pen/xVBOVQ?editors=001) | Function(triggerNode) | () => document.body |
| visible | determine whether the dropdown menu is visible | Boolean | - |
| onVisibleChange | a callback function takes an argument: `visible`, can be executed when the visible state is changing | Function | - |
You can get the menu list by `antd.Menu`, and set a callback function `onSelect` for it if you need. The menu items and the dividers are also available, by using `antd.Menu.Item` and `antd.Menu.Divider` respectively.
> Warning: You must set a unique `key` for `Menu.Item`.
| type | type of the button, the same as [Button](/components/button) | String | 'default' |
| onClick | a callback function, the same as [Button](/components/button), which will be executed when you click the button on the left | Function | - |
