I was building a ship in the VAB when I saw that every single decoupler isn't selectable, and when I put my mouse on it it says "Crossfeed toggles in Editor and Flight. Default off." which I'm sure isn't usually written. Any idea to resolve the issue ?
Thanks for the help.
EDIT : I restarted my game a few times and I can select and place my decouplers again, though the weird message is still showing. Seems to be resolved for now.