title: Margin Left in Constraint Layout on Android does not work
body: <p>I have tried to set the margins to a <code>ConstraintSet</code> into the <code>ConstraintSet.LEFT</code> anchor. But it doesn't work. However when using the <code>ConstraintSet.START</code> anchor, it works.</p>
  
  <p>I am using constraints programmatically, and I tried setting the margins with both <code>ConstraintSet.connect</code>, as in:</p>
  
  <p>(Does't work)</p>
  
  <pre><code>set.connect(view.getId(), ConstraintSet.LEFT, ConstraintSet.PARENT_ID, ConstraintSet.LEFT, MARGIN);
  </code></pre>
  
  <p>(Works)</p>
  
  <pre><code>set.connect(view.getId(), ConstraintSet.START, ConstraintSet.PARENT_ID, ConstraintSet.START, MARGIN);
  </code></pre>
  
  <p>And, I also tried with <code>ConstraintSet.setMargin</code>, as in:</p>
  
  <p>(Doesn't work)</p>
  
  <pre><code>set.setMargin(view.getId(), ConstraintSet.LEFT, MARGIN);
  </code></pre>
  
  <p>(Works)</p>
  
  <pre><code>set.setMargin(view.getId(), ConstraintSet.START, MARGIN);
  </code></pre>