title: Cannot set visibility on individual items in a ConstraintLayout.Group
body: <p>I have a <code>ConstraintLayout.Group</code> defined like this:</p>
  
  <pre><code>    &lt;android.support.constraint.Group
          android:id="@+id/someGroup"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          app:constraint_referenced_ids="
          textView1,
          textView2,
          button1" /&gt;
  </code></pre>
  
  <p>I change the visibility of this group from GONE to VISIBLE:</p>
  
  <pre><code>someGroup.visibility = VISIBLE
  </code></pre>
  
  <p>But when I try to override it by specifying the visibility of one of the views in that group:</p>
  
  <pre><code>button1.visibility = GONE
  </code></pre>
  
  <p>...it doesn't work. I log this visibility to logcat and it says <code>8 (GONE)</code>, <strong>but I can still see the view</strong>. </p>
  
  <p>Any ideas what might be happening here? I tried calling <code>requestLayout</code> and <code>updatePreLayout</code> on this group, I tried changing the visibility a few times, visible, invisible and then gone. I even rebuilt the whole project because some stackoverflow answer said that it might help for visiblity issues in ConstraintLayout. I also tried versions 1.1.3 and 2.2.0-alpha. Nothing worked. It's always visible.</p>