I’ll try to reproduce it tomorrow; after that I think it’s more of a display issue than anything else.
If you delete the first one, what’s probably happening is that the second one takes the first’s place (normal, it shifts up), except that the display isn’t refreshed so you get the impression that the second one was deleted (when it’s not).
I recommend you switch to the « Devices » box anyway
Indeed, I can reproduce the bug, it’s an old bug that must have been there from the beginning
It’s indeed a display-only bug (deletion does affect the correct widget), which occurs when you delete a « appareils de la pièce » widget above another « appareils de la pièce » widget of the same room only (very specific case).