title: Default Check not working on angular 2 radio button Form Control
body: <p>I have a formcontrol as radio buttons as follow</p>
  
  <pre><code> &lt;div class="form-group"&gt;
       &lt;label for=""&gt;Activity Time&lt;/label&gt;&lt;br/&gt;
       &lt;input type="radio" value="0" (change)="handleActivityTime(false)"   formControlName="activityTime"&gt; By Select
       &lt;input type="radio" value="1" (change)="handleActivityTime(true)"  [checked]="true" formControlName="activityTime"&gt; By Input
   &lt;/div&gt;
  
  </code></pre>
  
  <p>and in my component.ts I create the form control. Here I'm assigning the By Input as the default one and make it as checked. But it is not able to check. </p>