On Firefox using the Responsive Design Mode extension:
The "+" on the folder "searchdata" does not cause the folder to expand: https://www.screencast.com/t/jMJtBPBKFL .
At the Desktop size "+" to expand a folder in Resources does work.The 380x560 screen size does not have expand or collapse functionality.
On my iPhone 5s w/ latest iOS the folder searchdata does expand but does not display the "open" folder.
Neither updates the BreadCrumbs. Is that as designed?