Mixer context menus shouldn't scroll past the edge of the window

Issue type

UI bug (incorrect info or interface appearance)

Description with steps to reproduce

1. Make your MSS window smaller than your screen and move it to the left side of your screen
2. Open the Mixer in a score with lots of instruments
3. Open the sound picker for an instrument on the right end of the mixer and open several of the submenus
4. Leaving the menus open, scroll the mixer back to the left
5. See that the context menus fly outside the MSS window

Expected behavior: Once the button that triggers the context menu is no longer visible on the screen, close the context menus.

Supporting files, videos and screenshots

https://github.com/user-attachments/assets/ea4c5814-7887-43a7-b137-d5009efa3e49

In which versions of MuseScore Studio is this issue present?

All

Regression

No.

Operating system

macOS 15

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

Reproduce the issue by resizing and moving the MuseScore Studio window, opening the Mixer sound picker, expanding submenus, and scrolling the Mixer. Trace the Mixer context-menu behavior and make the work complete when menus close once their triggering button is no longer visible or menus cannot extend outside the window.