When sub-menus in mixer are overlapping they can be un-selectable or cause a crash

[zacjansheski]

Issue type

Crash or freeze

Description with steps to reproduce

1. Open dropdown to select sound for an instrument in the mixer
2. Be in the circumstance that the menus overlap
3. Select

In this circumstance the VST is not selected and the sub-menu closes

In this circumstance, attempting to select the VST causes a crash

Supporting files, videos and screenshots

video1009911132.mp4

What is the latest version of MuseScore Studio where this issue is present?

OS: macOS Sequoia (15.6), Arch.: arm64, MuseScore Studio version (64-bit): 4.6.0-252661331, revision: github-musescore-musescore-1ef30b2

Regression

Yes, this works in the latest released version and is broken in the nightly builds

Operating system

MacOS15

Additional context

No MacOS crash report appears after crashing

Checklist

• This report follows the guidelines for reporting bugs and issues
• I have verified that this issue has not been logged before, by searching the issue tracker for similar issues
• I have attached all requested files and information to this report
• I have attempted to identify the root problem as concisely as possible, and have used minimal reproducible examples where possible

[DmitryArefiev]

When sub-menus in mixer are overlapping they can be un-selectable

This issue can be related to Qt6.9 migration. I can't reproduce it in the old build based on Qt6.2:

Screen.Recording.2025-09-24.at.14.42.26.mov

(to reproduce you need to select instrument at the level Get more sounds menu)

[bkunda]

I can also reproduce this, but it has taken me a large number of tries to trigger any crashes.

The non-loading library (when a menu item overlaps "Get more sounds") is reproducible for me quite easily though.

What's good is that these issues seem to require a very specific arrangement of menu items; most of the time, the expanding menus avoid each other, so these issues don't manifest. IMO this makes this a good patch candidate (i.e. not a release blocker).