title: Problems with Layout Editor in Android Studio 2.2.1 using Constraint Layout
body: <p>I'm having trouble with Android Studio's Layout Editor after updating to Android Studio 2.2.1 (from stable channel). The editor is sometimes hiding "Constraint Layout" controls from the UI, as shown on the screenshots below:</p>
  
  <p><a href="https://i.stack.imgur.com/B8zg5.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/B8zg5.png" alt="Screenshot"></a></p>
  
  <p>I'm using Constraint Layout alpha 9 and Data Binding hence the layout is wrapped in "layout" tag. Here is the code for example layout:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;layout xmlns:android="http://schemas.android.com/apk/res/android"&gt;
  
      &lt;data&gt;
          &lt;variable
              name="viewModel"
              type="my.package.name.DashboardViewModel"/&gt;
      &lt;/data&gt;
  
      &lt;android.support.constraint.ConstraintLayout
          xmlns:android="http://schemas.android.com/apk/res/android"
          android:layout_width="match_parent"
          android:layout_height="match_parent"&gt;
      &lt;/android.support.constraint.ConstraintLayout&gt;
  &lt;/layout&gt;
  </code></pre>
  
  <p>The controls are disappearing and appearing when I add/remove elements from the layout. Is this a bug in the new Android Studio or Constraint Layout? Or am I doing something wrong?</p>