doc: remove new key way

components/modal/index.en-US.md

@@ -37,17 +37,7 @@ and so on.
 #### Destroy on close
 
 > The state of Modal will be preserved at it's component lifecircle.
-> If you wish to open it with brand new state everytime, you need to reset state manually. Or simply [give a new key](https://github.com/ant-design/ant-design/issues/4165) to Modal when visible is changed to `true`, React will treat it as a new component.
+> If you wish to open it with brand new state everytime, you need to reset state manually.
-
-> ```jsx
-> <Modal key={this.state.newKey} visible={this.state.visible} />
-> ```
-
-> Another way is to conditionally mount modal.
-
-> ```jsx
-> {this.state.visible && <Modal visible={true} />}
-> ```
 
 ### Modal.method()
 

components/modal/index.zh-CN.md

@@ -36,17 +36,7 @@ title: Modal
 #### 清空旧数据
 
 > `<Modal />` 组件有标准的 React 生命周期，关闭后状态不会自动清空。
-> 如果希望每次打开都是新内容，需要自行手动清空旧的状态。或者打开时给 Modal 设置一个[全新的 key](https://github.com/ant-design/ant-design/issues/4165)， React 会渲染出一个全新的对话框。
+> 如果希望每次打开都是新内容，需要自行手动清空旧的状态。
-
-> ```jsx
-> <Modal key={this.state.newKey} visible={this.state.visible} />
-> ```
-
-> 另一种方式是根据条件加载 Modal。
-
-> ```jsx
-> {this.state.visible && <Modal visible={true} />}
-> ```
 
 ### Modal.method()