title: Android Studio 2.2 not displaying view properties
body: <p>After upgrading my android studio to version 2.2 i'm getting following error when i click on a view in layout designer to see it properties:</p>
  
  <blockquote>
    <p>Exception in plugin Android Support Moments Ago. </p>
    
    <p>Missing attribute definition for focusable
    java.lang.IllegalArgumentException:</p>
    
    <p>Missing attribute definition for focusable
        at com.android.tools.idea.uibuilder.property.NlPropertyItem.(NlPropertyItem.java:88)
        at com.android.tools.idea.uibuilder.property.NlPropertyItem.create(NlPropertyItem.java:72)
        at com.android.tools.idea.uibuilder.property.NlProperties.getPropertiesWithReadLock(NlProperties.java:111)
        at com.android.tools.idea.uibuilder.property.NlProperties.lambda$getProperties$537(NlProperties.java:64)
        at com.intellij.openapi.application.impl.ApplicationImpl.runReadAction(ApplicationImpl.java:966)
        at com.android.tools.idea.uibuilder.property.NlProperties.getProperties(NlProperties.java:63)
        at com.android.tools.idea.uibuilder.property.NlPropertiesManager.lambda$setSelectedComponents$228(NlPropertiesManager.java:174)
        at com.intellij.openapi.application.impl.ApplicationImpl$8.run(ApplicationImpl.java:369)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at java.lang.Thread.run(Thread.java:745)</p>
  </blockquote>
  
  <p>and Properties panel stuck on loading,</p>
  
  <p>My OS is ubuntu 16.04 and almost i have upgraded everything in Android SDK to the latest version.</p>