But sometimes it is necessary. For example, since I can’t (or don’t know how) change a key signature at a D.S. al coda (since the D.S. is in a different key) and change the Coda to a different key all together, I create a blank measure before the coda with the key change. If I could hide the barline, then it would look correct. There are legitimate reasons for wanting a hidden bar line. Instead of the implication that we shouldn’t need to do it or it is wrong, the user should be able to notate however they want (within the limits of technology), not be forced to do something the way the designers think they should be done. Apologies if I can do the key change I’m after.