You can manually manage this setting in "Assets/Plugins/Infinity Code/Ultimate Editor Enhancer Settings/LocalSettings.asset".

Thanks for showing me the problem.
In the next version, I'll add this to Quick Access Bar settings, and make Restore Defaults Settings restore that value too.

Although I found that I could reopen it by hovering over the screen border.

didn't restore this in the restore settings menu.

I wanted know if my project is the problem
and had to create a new project and test it.

If I had restored the quick "quick access bar collapse" from Restore Settings, I wouldn't have gotten this far.