title: Antd Menu.SubMenu keeps collapsing on hover
body: <p>I am having trouble with the Antd submenu. If I use the code below, the submenu opens on hover, but it will close again if the mouse is not exactly hovering the link in the first item.</p>
  
  <p>Any idea what I can do about this? I'm using v3.0.0-beta.5</p>
  
  <p>Here is a screen recording:</p>
  
  <p><a href="https://www.dropbox.com/s/jdxakivocf5atgs/antd-submenu-bug.mov?dl=0" rel="nofollow noreferrer">https://www.dropbox.com/s/jdxakivocf5atgs/antd-submenu-bug.mov?dl=0</a></p>
  
  <p>Maybe it's just a bug in the beta version, but submitting an issue to the antd repo requires a lot of effort unfortunately and doesn't even include 3.0 in their app and fork boilerplate.</p>
  
  <pre><code>import React from 'react';
  import { Link } from 'react-router-dom';
  import { Menu, Avatar } from 'antd';
  const { SubMenu, Item, Divider } = Menu;
  import styled from 'styled-components';
  
  const Box = styled.span`
    position: relative;
    display: flex;
    align-items: center;
    height: 64px;
  `;
  
  interface INavigationProps {
    onLogout: () =&gt; any;
    isAuthed: boolean;
    avatar?: string;
  }
  
  export const Navigation: React.SFC&lt;INavigationProps&gt; = ({
    isAuthed,
    onLogout,
    avatar,
  }) =&gt;
    isAuthed &amp;&amp; (
      &lt;Menu mode="horizontal" style={{ lineHeight: '64px' }}&gt;
        &lt;Item key="admin"&gt;
          &lt;Link to="/admin"&gt;admin&lt;/Link&gt;
        &lt;/Item&gt;
        &lt;SubMenu
          key="user"
          mode="inline"
          title={
            &lt;Box&gt;
              &lt;Avatar src={avatar} icon="user" /&gt;
            &lt;/Box&gt;
          }
        &gt;
          &lt;Item key="user.profile"&gt;
            &lt;Link to="/profile"&gt;profile&lt;/Link&gt;
          &lt;/Item&gt;
          &lt;Divider /&gt;
          &lt;Item key="user.logout"&gt;
            &lt;Link to="/" onClick={onLogout}&gt;
              logout
            &lt;/Link&gt;
          &lt;/Item&gt;
        &lt;/SubMenu&gt;
      &lt;/Menu&gt;
    );
  
  export default Navigation;
  </code></pre>