title: Is it possible to show/hide an element in a parent without rerendering?
body: <p>Please correct me if my thought process differs from the orthodoxy of React.js..</p>
  
  <p>I have a parent <code>&lt; MainViewController /&gt;</code> that has a <code>&lt;View /&gt;</code> child. </p>
  
  <p>If a scrolling event happens in my <code>&lt;View /&gt;</code>, then I want to show/hide a button in my parent <code>&lt; MainViewController /&gt;</code>. </p>
  
  <p>Unfortunately right now, I'm doing <code>setState</code> to toggle, but it rerenders parent, and consequentially, all of its children. Basically, it resets my entire app. Is there a simpler way to toggle hide/show without rerendering?</p>
  
  <p>My relevant code :</p>
  
  <pre><code>var MainViewController = React.createClass({
    getInitialState () {
      return {
        showAskQuestion: false,
      };  
    },
    toggleFloatingButton () {
      this.setState({
        showAskQuestion: !this.state.showAskQuestion
      });
    },
      render () {
          return (
              &lt;Container&gt;
                  &lt;UI.NavigationBar name="main" /&gt;
          &lt;UI.Button type="info" className={ this.state.showAskQuestion ? '' : 'hidden' } &gt;
            Ask A Question
          &lt;/UI.Button&gt;      
                  &lt;ViewManager name="main" defaultView="tabs"&gt;
                      &lt;View name="tabs" component={TabViewController} toggleFloatingButton={this.toggleFloatingButton} /&gt;
                  &lt;/ViewManager&gt;
              &lt;/Container&gt;
          );
      }
  });
  </code></pre>