Inserting measure before measure previously at start of system displays spurious key signature

• Dec 7, 2018 - 16:53
Reported version
P0 - Critical
S3 - Major

Take the enclosed 3.0-fresh (19499) score. Select any measure. Shift-I. A measure arises, but carries a superfluous key-signature which cannot be deleted.

Attachment Size
Fuga_a_1.mscz 17.46 KB


Priority P0 - Critical

I am able to reproduce, but not that simply. It works fine for me at first, then starts to fail. Not sure of the complete steps needed to reproduce, but it might involve either repeated attempts to add measures and then undoing, or perhaps accidentally inserting a frame then undoing that...

How about line break - any chance you added one of those then deleted it? I see the same effect that way. As I said, I don't see this behavior when I first load the score. Have you tried closing it, reopening it, and verifying if this is true for you? But once the score gets into this state, it's there until I delete the measure.

The following reproduces the problem for me reliably:

1) load the score in the original post
2) select measure 12 (could be any measure after 1)
3) double-click text frame icon in Frames & Measures palette (or, add line break to measure 11)
4) undo, or select and delete
5) reselect measure 12
5) double-click measure icon in Frames & Measure palette

Result: the inserted measure shows a key signature unnecessarily.

I can also reproduce that particular sequence in a score created from scratch - default score, add key signature at beginning, then follow the above steps. But the key for me is adding then removing the frame.

As for workarounds, I actually see a couple. One is to simply delete the measure and add it again. It also works to add a new key signature there then delete that.

When it gets into that state, you can't delete that (or any) measure. No, I didn't use any breaks/spacers. Overwriting the signature with a real one produces one that can then be deleted, but I still can't delete the measure.

OK. Well, based on my analysis, I have a fix for what I was able to reproduce. There are actually quite a few ways for a score to get into the state where inserting measures would have this effect, inserting and removing frames or breaks are but two of them. Basically, anything that would result in the measure question having once upon a time been at the beginning of the system would do it - there would forever be a vestige of the key signature in that system, ready to reappear on the (insert measure) command. The fix is simply to be sure to ignore that vestige when inserting measures.

I really cannot imagine any way the measure would not be deletable though, and nothing about my fix would address that. If you are ever able to reproduce that state, let us know by filing a new issue report, and maybe see if you can leave that file open long enough for someone to respond and have you try a few things.

When I was in this state, inserting measures not near the beginning of a line (actually, they were at the end) brought forth measures with bogus signatures repeatedly (at the same point).

Speaking of, is there a reliable way to find "corrupt measures" without saving online? I created a sea of corruption Saturday night by repeated use of timewise insert and delete in one voice (the other voices were empty, but were thereby corrupted) and was almost unable to upload.

The same corruption should get reported by MuseScore on opening the score. So for corruptions that crept in in the current session, save/close/reopen should show them the same way that "Save online" does


Adding a command , e.g. in the Tools section of the menus, and/or via a shortcut might be a good idea. As would calling that function automagically on every "Save" or "Save as" (but probably not on autosave)
Feel free to submit such a feature request

In reply to by Marc Sabatella

It's a bit problematic product-wise (imagine a "show thieves" button for a government), but at very least, for a beta, it would be very welcome. Certainly, save(-as) should show the complaint dialog and offer not to save. By the way, what is a little blue "+" (or sometimes "-") placed by the app above the staff?

Title 3.0 Inserting measure (Shift-I, Mac Mojave) inserts bogus key signature. Inserting measure before measure previously at start of system displays spurious key signature