bugfix:fix #3878, In the top mode. Menu will follow the slide (#3928)

* bugfix:fix #3878, In the top mode. Menu will follow the slide

* typo: repalce warp to wrap

src/components/SiderMenu/BaseMenu.js

@@ -123,6 +123,17 @@ export default class BaseMenu extends PureComponent {
     return `/${path || ''}`.replace(/\/+/g, '/');
   };
 
+  getPopupContainer = (fixedHeader, layout) => {
+    if (fixedHeader && layout === 'topmenu') {
+      return this.wrap;
+    }
+    return document.body;
+  };
+
+  getRef = ref => {
+    this.wrap = ref;
+  };
+
   render() {
     const {
       openKeys,
@@ -131,6 +142,8 @@ export default class BaseMenu extends PureComponent {
       location: { pathname },
       className,
       collapsed,
+      fixedHeader,
+      layout,
     } = this.props;
     // if pathname can't match, use the nearest parent's key
     let selectedKeys = this.getSelectedMenuKeys(pathname);
@@ -149,6 +162,7 @@ export default class BaseMenu extends PureComponent {
     });
 
     return (
+      <>
         <Menu
           key="Menu"
           mode={mode}
@@ -158,9 +172,12 @@ export default class BaseMenu extends PureComponent {
           style={style}
           className={cls}
           {...props}
+          getPopupContainer={() => this.getPopupContainer(fixedHeader, layout)}
         >
           {this.getNavMenuItems(menuData)}
         </Menu>
+        <div ref={this.getRef} />
+      </>
     );
   }
 }