title: multiTemplateDataRows, error There can only be one default row without a when predicate function
body: <p>I have added multiTemplateDataRows to my     <code>&lt;mat-table multiTemplateDataRows&gt;</code></p>
  
  <p>and have the following rows:</p>
  
  <pre><code>&lt;mat-header-row *matHeaderRowDef="data.displayedColumns"&gt;&lt;/mat-header-row&gt;
  &lt;tr mat-row *matRowDef="let row; columns: data.displayedColumns;"&gt;&lt;/tr&gt;
  &lt;tr mat-row *matRowDef="let row; columns: ['detail'];"&gt;&lt;/tr&gt;
  </code></pre>
  
  <p>but i still receive the error "There can only be one default row without a when predicate function."</p>