Ghost "Staff/Part Properties..." Crash

Hi! Hope this isn't a dupe report.

If you click an instrument name but then right click any other part of the canvas and choose "Staff/Part Properties...", it will enter a ghost instrument's options and therefor crash when performing any action.

Repro:
- Left click a long instrument name text (eg. "Violin" right before the first measure)
- Right click on a blank part of the page (NOT the instrument name)
- Click "Staff/Part Properties..."
- The "Long instrument name:" and "Short instrument name:" fields should be blank
- Perform any action, eg. "Apply"
- MS4 will crash, presumably because we're in a menu for a "ghost" instrument?

Expected:
- Right clicking a blank part of the canvas shouldn't bring up the "Staff/Part Properties..." options. It seems like a residual from the previous action where the instrument name was selected.

Windows 10 Version 2009, Arch.: x86_64, MuseScore version (64-bit): 4.0.2-230651553, revision: dbe7c6d