replace multicam clip/angle

I've got a multicam clip that I auto synced. I then graded 2 angles in Resolve, and reimported them with new names.

I've opened the multicam clip and I want to replace the ungraded angles with the newly imported graded ones.

So I drag a graded clip over it's ungraded version and wait for the pop-up that lets me replace the original, but it's not popping up and the graded clip is cutting into the old one wherever I place the cursor.

I'm sure this was working yesterday! How do I replace the ungraded clip with the graded one and maintain it's place on the timeline?

came back from lunch and now it's working!

Yes, FCPX requires you have lunch first. I think that's in the user manual somewhere.

I'm permanently out to lunch!

It sometimes requires you to have a few beers with that lunch !