title: Ionic 3 Tabs only show specific html in one tab
body: <p>I am using Ionic 3 tabs and I want that this <code>&lt;ion-fab&gt;</code> only would be seen in first tab :</p>
  
  <p>HTML PAGE : </p>
  
  <pre><code>&lt;ion-tabs&gt;
    &lt;ion-tab [root]="tab1Root"&gt;&lt;/ion-tab&gt; //first tab
    &lt;ion-tab [root]="tab2Root"&gt;&lt;/ion-tab&gt;
    &lt;ion-tab [root]="tab3Root"&gt;&lt;/ion-tab&gt;
  &lt;/ion-tabs&gt;
  //Show this only if first tab : 
      &lt;ion-fab ngif="tabIndex = 0"&gt;&lt;/ion-fab&gt;
  </code></pre>