I was about to suggest to THOM [above], that he define a hooked alcove to either use as the only one that accepts 'essence_air' items, or to use for those few alcoves that refuse them ~but it didn't work.

It was only odd whimsy that I bothered to even check that in the editor; it being all but a given by this point; or so I had thought.
I confirmed that the hook was being run, and that the return of false did not stop me from placing the item on the surface.
This functionality is changed?