Version 3.0.6067
Steps to Recreate:
1. Switch to Compact Player mode
2. Musicbee Menu | Customize Panel
3. Under the 'Stack' section on the right, check the box for 'Ticked elements are displayed as tabs'
4. Save
5. Go back to Musicbee Menu | Customize panel and make changes to the panel settings (e.g. adding/removing elements, changing elements from unstacked to stacked) and Save.
6. go back to Musicbee | Customize panel
Expected: Changes made in step 5 should be saved
Actual: Settings changes made in step 5 are not retained.
I'm only seeing this happen if the stack mode is set to display as tabs, if I set it to display using the selector I'm seeing my changes retained.
Also recorded video demonstration here:
https://youtu.be/n3nrjAPPwqw