Adding ‘new data columns’ in the UX - behaves in an odd (but logical) (but wrong) way:
- you are in the UX
- you love the data part of the bottom left
- you think - cool, I can add a new column I need
- so you add
BUT you cannot find the new columns… and think you have screwed up.
Fear not! the feature just does not work properly (it seems 
You are in a tab connected to a sheet, and you see data from a row from that sheet
—> expected behavior - you are adding a new column to that sheet
No - you are adding a new column to the first sheet in your app (the top of the list in the data editor, according to Glide).
Weirdness explained - and a bug to be fixed, please 
