RENAMING A FOLDER
RENAMING A FOLDER HIDES THE SUBFOLDERS... FIX PLEASE. I THOUGHT THE SUBFOLDERS WERE GONE FOREVER UNTIL I RENAMED BACK TO THE ORIGINAL. THEN THEY REAPPEARED.

-
Athak commented
Just to add my experience to the comment above, the subfolder is not exactly 'hidden', rather it is dislodged. When viewing all accounts, renaming the parent folder will result in the subfolder disappearing. Switching to the particular account the folder belonged to, the subfolder has become a top level folder and can be found in the top of the hierarchy. This was my experience with local folders, can't vouch it's the same with imap folders. very disruptive bug/behaviour either way.