Michael, maybe some sense is sinking in on this end.

I needed to flatten my wonky curves before booling a domed object so, the flat plane the curves were projected to was a surrogate. Projection's *default setup* seems intended for use with the final surface - not temps - BUT, your "Disable update" button retains the curves and allows me to replace the temp surface with the target surface.

If this is not correct, "oh well" (sigh), but your "Disable button" did-the-trick!

Thanks.

Leonard