title: How to attach a matTooltip to a disabled mat-tab?
body: <p>I want to attach a matTooltip to a mat-icon in a disabled mat-tab but... it seems that this function is disabled when the mat-tab is disabled.
  Has anybody got same problem ?</p>
  
  <p>(I can't put the mat-tab in a div of course)</p>
  
  <p>Thank you.</p>
  
  <pre><code>&lt;mat-tab label="Tab 3" [disabled]="!picExist" &gt;
      &lt;ng-template mat-tab-label&gt;
      &lt;mat-icon *ngIf="picExist" matTooltip="See Pictures"&gt;photo_camera&lt;/mat-icon&gt;
      &lt;mat-icon *ngIf="!picExist" matTooltip="No picture!"&gt;add_a_photo&lt;/mat-icon&gt;
      &lt;/ng-template&gt;
      &lt;div&gt;The content&lt;/div&gt;
  &lt;/mat-tab&gt;
  </code></pre>