It is laggy and freezes alot. But it is an amazing concept.

don't work with dark themes(it has white background)

Awesome concept, works pretty well although it's a bit clunky when you turn off a stylesheet it reloads the whole tab not just the compatibility section. Also there's no dark theme icon!

Nice! Would be cool too have some filters (e.g with checkbox) for views. E.g. filter browser view to only show versions with compatibility problems, filter css view to only show rules with problems. Would be easier to quickly browse through problems.

This addon is awesome. I love the idea.
I wish it showed a column for safari though. I don't have a mac, so safari testing is always a challenge.