Is it just me, or are gears showing up where they shouldn't. It certainly could be a local *css override that is causing it, and if so then a good answer would have a reference to some documenation that would help with finding bad customizations.
What do you think about some kind of validator for *css that warns about stuff that could conflct with the styling frameworks? It might be easier than either documenting it or exteded UX code (in the long run best, but harder).
Are you using the latest code? There were some kinks in the early releases with the new menu.
I don't think there's any getting around the need for documentation. If someone wants to write a validator, I won't stop them, but I can't really fathom how that would work. I don't think there's anything as good as an eyeball at detecting bad customizations.
I agree generally about the eyeballing, but I think there are things it could do. It could notice when important settings are overriden (or not, I just found another css bug in my customization. I suppressed the external link icon, but the padding had !important and the override didn't work without !important). I think there are some significant patterns that could be helpful to find. I suppose it's even harder to figure out which customizations (*css) have their visibility changed with a style/theme/migration based change, but that would be really useful too.
you could regenerate CSS/JS with these: