Can't un-indent first line of music
I have the attached file that I didn't create but am trying to edit. I want to un-indent the first line. In searching online, I've found two possible ways to do this, neither of which seem to apply here. I can't see that there's any frame to delete (and I do have "Show Frames" enabled). And the instrument names are blank, so they aren't taking up space in front of the staff.
I'm using MuseScore 2.3.2, and when I check for updates, it says I'm up to date. I'm on Mac OS Mojave (10.14).