Unfortunately that’s not possible and for some extra info for the bug-reporter the specific prop rakan_912 seems to be reffering to is this prop in the “Lava Tiles Gallery” as when I placed it down it was unselectable by the phone tool
Mineblo confirmed its not a creative thing.
In UEFN you can replace a pieces with a different piece, I used this once to delete an undeletable by swapping it to something else which could be deleted.
It needs to be fixed… trigger the AI bug-reporter by adding votes.
You’ll hafta live with it at the moment… like the funny bit in a set of fancy house plans that defies structural sense and needs to be worked around… Hey!!, make it into a feature…