docs: FAQ about dropdownRender (#37906)

components/select/index.en-US.md

@@ -115,6 +115,25 @@ It's caused by option with different `label` and `value`. You can use `optionFil
 
 You can control it by `open` prop: [codesandbox](https://codesandbox.io/s/ji-ben-shi-yong-antd-4-21-7-forked-gnp4cy?file=/demo.js).
 
+### I don't want dropdown close when click inside `dropdownRender`?
+
+Select will close when it lose focus. You can prevent event to handle this:
+
+```jsx
+<Select
+  dropdownRender={() => (
+    <div
+      onMouseDown={e => {
+        e.preventDefault();
+        e.stopPropagation();
+      }}
+    >
+      Some Content
+    </div>
+  )}
+/>
+```
+
 ### Why sometime customize Option cause scroll break?
 
 Virtual scroll internal set item height as `32px`. You need to adjust `listItemHeight` when your option height is less and `listHeight` config list container height:

components/select/index.zh-CN.md

@@ -116,6 +116,25 @@ cover: https://gw.alipayobjects.com/zos/alicdn/_0XzgOis7/Select.svg
 
 你可以使用受控模式，手动设置 `open` 属性：[codesandbox](https://codesandbox.io/s/ji-ben-shi-yong-antd-4-21-7-forked-gnp4cy?file=/demo.js)。
 
+### 反过来希望点击 `dropdownRender` 里元素不消失该怎么办？
+
+Select 当失去焦点时会关闭下拉框，如果你可以通过阻止默认行为避免丢失焦点导致的关闭：
+
+```jsx
+<Select
+  dropdownRender={() => (
+    <div
+      onMouseDown={e => {
+        e.preventDefault();
+        e.stopPropagation();
+      }}
+    >
+      Some Content
+    </div>
+  )}
+/>
+```
+
 ### 自定义 Option 样式导致滚动异常怎么办？
 
 这是由于虚拟滚动默认选项高度为 `32px`，如果你的选项高度小于该值则需要通过 `listItemHeight` 属性调整，而 `listHeight` 用于设置滚动容器高度：