Parts are displayed at very large zoom level when the Navigator is activated

[Rabadman]

Issue type

Other type of issue

Bug description

Regardless of the default setting for the worksheet size, the parts are displayed much too large (0%) when the navigator is activated.

Steps to reproduce

1. Start MuseScore, open a score and activate the Navigator in the menu under View
2. Go to Edit/Preferences and set the default zoom to one of the available settings under Canvas
3. Close MuseScore and start MuseScore with the Navigator already activated
4. Open a score with already created parts.
5. The full score is displayed in the set size.
6. Switch to one of the parts
7. The display of the part excerpts is much too large (0%)

Screenshots/Screen recordings

MuseScore Version

4.3.1

Regression

No.

Operating system

Windows 10

Additional context

No response

[cbjeukendrup]

Actually a duplicate of #15591, but clearer, so I'll keep this one open and close the other one