Maximum of 20 instruments available with screen reader in the export dialogue box

Issue type

Accessibility issue (e.g. for keyboard-only or screen reader users)

Description with steps to reproduce

Using a screen reader it seems to be impossible to get to instruments beyond the first 20 in the export dialogue box parts list.

It seems the navigation cycles back to the top of the list after the first 20 parts, but only if the list is not also scrolled with the mouse. Normally for me only the first 10 or so instruments are visible at since, so as soon as you navigate past there with the keyboard, you can't see what is happening. If you then scroll the list so you can see what's happening while navigating, you navigate all the way to the bottom of the list. But if you don't scroll the list, then it cycles back to the top after 20 presses of the Down key. So a sighted user wanting to reproduce this will want to just count keypresses or enable their screen reader but not touch the mouse to check on the progress of the navigation.

To reproduce:

1. Open a large score with over 20 parts, such as this big orchestral score: https://musescore.com/user/7477891/scores/6525359
2. Go to the export dialog in the file menu.
3. Tab to the place that lets you select parts to export. The first entry should be main score.
4. Go through the list of available part. For instance, if this is an orchestral part, look for the cello part. It will be way down the list of instruments because woodwinds, brass, and percussion come first.
5. For a screen reader user, you get to, say, the 20th part, which is trombone, and then it cycles back to main score. This means you can't specifically select the cello or violin parts for export.

credit to @msviolafangirl for diagnosing the issue.

Supporting files, videos and screenshots

N/A

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

4.4

Regression

I was unable to check

Operating system

Windows 11 with NVDA

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 in the export dialogue's parts list using a large score and keyboard navigation with a screen reader or by counting Down-key presses. Start from the export dialogue and its part-selection control; done means keyboard and screen-reader users can reach and select every instrument, including parts beyond the first 20, without navigation cycling back prematurely.