title: android studio 3.0 noting show any things in device file explorer
body: <p>in android studio 3.0 preview canary 4 nothing show any thing of my device in new device file explorer in android studio 3. 
  i enable USB debugging and can run my app and can show file in DDMS. 
  <a href="https://i.stack.imgur.com/Uu5MR.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Uu5MR.png" alt="enter image description here"></a></p>