title: React event onMouseLeave not triggered when moving cursor fast
body: <p>Im trying to implement hover event but onMouseLeave is not always triggering when leaving element especially when moving cursor over elements fast. I tried i Chrome, Firefox and Internet Explorer but in every browser same problem appeared.</p>
  
  <p>My code:</p>
  
  <pre><code>import React from 'react';
  import Autolinker from 'autolinker';
  import DateTime from './DateTime.jsx'
  class Comment extends React.Component{
  
       constructor(props){
          super(props);
          this.handleOnMouseOver = this.handleOnMouseOver.bind(this);
          this.handleOnMouseOut = this.handleOnMouseOut.bind(this);
          this.state = {
              hovering: false
          };
      }
  
      render(){
          return &lt;li className="media comment" onMouseEnter={this.handleOnMouseOver} onMouseLeave={this.handleOnMouseOut}&gt;
              &lt;div className="image"&gt;
                  &lt;img src={this.props.activity.user.avatar.small_url} width="42" height="42" /&gt;
              &lt;/div&gt;
              &lt;div className="body"&gt;
                  {this.state.hovering ? null : &lt;time className="pull-right"&gt;&lt;DateTime timeInMiliseconds={this.props.activity.published_at} byDay={true}/&gt;&lt;/time&gt;}
                  &lt;p&gt;
                      &lt;strong&gt;
                          &lt;span&gt;{this.props.activity.user.full_name}&lt;/span&gt;
                          {this.state.hovering ? &lt;span className="edit-comment"&gt;Edit&lt;/span&gt; : null}
  
                      &lt;/strong&gt;
                  &lt;/p&gt;    
               &lt;/div&gt;
          &lt;/li&gt;;
      }
  
  
      handleOnMouseOver(event){
           event.preventDefault();
           this.setState({hovering:true});
      }
  
      handleOnMouseOut(event){
          event.preventDefault();
          this.setState({hovering:false});
      }
  
       newlines(text) {
          if (text) 
              return text.replace(/\n/g, '&lt;br /&gt;');
  
      }
  
  
  
  }
  
  export default Comment;
  </code></pre>