NewOutlook
Outlook: Categorize Emails by Dragging Them onto a Favorite Category
Users can now drag emails onto favorite categories to apply categorization without opening menus or right-clicking. This is a convenience feature for inbox organization with no admin action needed.
Microsoft's description
You can now add a category to your Favorites and then drag emails right onto it to apply that category. No need to open menus or right-click each message. Just pin the category you use most to Favorites, then drop your emails on it to tag them in one quick motion. It's a faster, more visual way to keep your inbox sorted the way you like. #newoutlookforwindows