I have a user who is having an issue with a Favorited Folder, the Folder's tab within the Favorites drop down was greyed out and inaccessible, we were able to access the mailbox from the main folder below and create a new, working tab for it under Favorites, but the old tab remains there, unusable and undeletable. I am unable to move the folder, click the folder, or right click the folder yet it takes up the space and can't be overlapped.
