title: How can I hide and unhide the project folder tree in sublime-text
body: <p>I can no longer see the project folder navigation tree on the left side of my interface. </p>
  
  <p>I suspect I have hit some shortcut by accident that made it go away. </p>
  
  <p>What are the shortuts to make the project folder navigation tree hide and unhide in sublime text?</p>