Search All Folders Option
I have a number of Rules setup to divert incoming mail to specified folders. Sometimes it's difficult to find messages that may have been moved to one of those folders or is linked to a Conversation chain. Search also seems to be impacted by whether the message has Read or Unread.
The Outlook Desktop Application allows the user to specify whether to search the Search Current Folder or Search All Folders. That option would be useful in the mobile Apps.