title: Android Studio 3.3 RC3 Theme Editor Missing
body: <p>Since installing Android Studio 3.3RC3 from the preview site, the Theme Editor is missing. When viewing my <code>styles.xml</code> file, there is no button to open the theme editor.</p>
  
  <p>Pressing SHIFT twice and searching for the Theme Editor reveals the icon, but when the pane comes up it shows a blank text editor.</p>
  
  <p><a href="https://i.stack.imgur.com/6WrsF.png" rel="noreferrer"><img src="https://i.stack.imgur.com/6WrsF.png" alt="enter image description here"></a></p>
  
  <p><a href="https://i.stack.imgur.com/qzYCq.png" rel="noreferrer"><img src="https://i.stack.imgur.com/qzYCq.png" alt="enter image description here"></a></p>