This would be especially useful for creating rules. To create rules you have to grab info from messages (subject, sender info etc) and without the ability to create tabs, you have to constantly go back and forth which can be tedius.
The ability to collapse subtags under the parent tag on the mobile app
It would be super helpful if you could collapse all subtags under the parent tag on mobile. If you have a lot of tags it takes a lot of scrolling to be able to get through them all to get to a tag group that's listed closer to the bottom