I discovered the Flagged Mail 'Smart' folder this morning.  Clicked on one of the flagged emails, but clicked too far to the right, which cancelled the flag and the email disappeared from the list.  Did a search for it, reapplied the flag, then went to return to my inbox and was asked if I wanted to save the changes to the 'Smart' folder, which I did, and now the Flagged Mail 'Smart' folder only contains the emails from the results of the search that I did!  I really do NOT like this Outlook!!  It's riddled with booby traps.