I have organized my workspace with Folders and Sub-folders. When I click the dropdown arrow beside a top level folder the content of that folder appears below. Spectacular! Here's the rub though....when I click the dropdown arrow beside a sub-folder absolutely nothing happens. I am forced to click the folder to open the contents in the right hand pane. This makes navigating between different content cumbersome.
Add the capability to click on the dropdown arrow for any folder (top level or sub-folders) and show all folder content in the navigation pane. Clicking on an item in the navigation pane (folder or document, etc) have the detail open in the right hand pane.