I might be missing something really obvious here, but I swear there was a “Display at Table” toggle on the relations tables when in the edit layout screens. I was using that toggle as recently as yesterday while customising the layout of a large table into multiple columns for easy viewing. The default view seems to still have what I want in that the relation is a lookup of the default column. But as soon as I go to edit the layout, the relation goes to a table view. Has the toggle moved somewhere else?
To reproduce:
Create two tables and then add two way relation column between them
Add a row to each of the tables
Expand one of the rows
This is the default layout and the relation will be a dropdown of the values from the other table
Go up to Edit Layout
The relation is now showing a full table view instead of the simplified dropdown
I can’t seem to make it go back to just a dropdown while in a non-default layout
Well, I looked everywhere but couldn’t find the toggle either …
I’m also not sure why only linked relation fields are forcibly displayed as subtables …
I mean, why not also relation fields ?
From what I’ve seen in the detail layout editor relation fields could be potentially interpreted as select list instead of relation fields, for some reasons …
(unless it was working like this previously )
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: It’s a known bug which is currently worked on 
! So it should be fixed real soon !