I’m organizing my emails into various subfolders which have subfolders of their own again. In addition, I’m using rules to automatically move messages to their corresponding folder.

Usually I keep this folder structure collapsed but then I can’t see if a message arrived in any of these subfolders. Even these folder trees are expanded, I would have to scroll in order to see them all.

Is there a way to make the parent folder show the combined amount of unread items in any of the subfolders?