Java syntax colors and settings don't save

_Originally reported in [Bug 486992](https://bugs.eclipse.org/bugs/show_bug.cgi?id=486992) and more recently in https://github.com/eclipse-packaging/packages/issues/54_

When in dark theme (but perhaps other cases too based on comments) when unchecking Bold in `Keywords, excluding 'return'` it's not maintaining the bold font I set.

@valmirserpa kindly made a screen recording in https://github.com/eclipse-packaging/packages/issues/54#issuecomment-1709163594 which I embed here as the original was not necessarily stored in a permanent location:

https://github.com/eclipse-jdt/eclipse.jdt.ui/assets/679236/c7f8d445-6683-409e-b6f2-7df0febc5ab9