Unable to close score or quit MSS with opened VST plugin window (5.0 main)

[DmitryArefiev]

Issue type

Crash or freeze

Description with steps to reproduce

1. Open score
2. Open audio FX plugin window (any)
3. Click on X to close score ('Do you want to save changes to the score..' message doesn't appear)
4. After that you can't close score or quit MSS (only terminate process from Task manager)

Supporting files, videos and screenshots

bandicam.2026-09-01.22-14-00-533.mp4

In which versions of MuseScore Studio is this issue present?

5.0.0-260901031 (nightly main)

Regression

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

Operating system

Windows 10 (or macOS)

Additional context

No response

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