Copying a tempo element to a palette doesn't save whitespace between "=" and digits

Issue type

UX/Interaction bug (incorrect behaviour)

Description with steps to reproduce

1. Create a tempo element
2. Modify the whitespace between "=" and the tempo digits by either changing the font used, or size (pt) of the whitespace character
3. Control + Shift + Left click drag into a palette to create a custom palette item
4. Saved element will delete the white space between "=" and digits

Supporting files, videos and screenshots

2. (changing the font, or the size, or both will affect this behaviour)

3. (newly added element added highlighted in red)

4. (Adding custom element back onto the score, whitespace removed, you can also see it in the preview)

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

Musescore 4.5.2

Regression

I was unable to check

Operating system

Windows 11

Additional context

Adding additional whitespaces or removing it entirely between "=" and digits has the correct behaviour

e.g.

Additionally, this may also affect control + c copying

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 MuseScore Studio 4.5.2 on Windows 11 by modifying the whitespace in a tempo element, copying it into a palette, and adding it back to a score. Compare the original, palette preview, and restored element, then check whether Control+C shows the same behavior. Done means the customized whitespace between '=' and the tempo digits is preserved.