Nothing happens when I click on a drive or top-level directory

[rtbailey]

If I click on C:  or  C:\some_top_dir  nothing happens in the tree view. 
If I click on C:\some_top_dir\sub_dir, then sub_dir gets selected and I see its contents in the file view to the right.
If in the file view of sub_dir, I click on <-..  nothing happens there either.
If I select a drive from the drive dropdown, nothing happens.
So there is no way I can get a listing of my top-level directories .

OH, I SEE THE PROBLEM.  I AM IN A LOCKED TAB.  I SUPPOSE I CAN REMEMBER NOW NOT TO DO THAT,
BUT IT WOULD BE GOOD IF YOU COULD PUT A MESSAGE IN THE HINT BOX OR STATUS LINE IF A
STUPID USER TRIES TO DO WHAT I JUST DID.

[Mathias (Author)]

You can also enable "Open new tab when going to new location if tab is locked" in Explorer Panel settings