Don't know why i did not switch much earlier to Stylus (WebExt) :-)

Since brandnew Stylish version 3.0.1 (update to WebExt) is totally broken right now i encountered Stylus and it's way better than Stylish and has some very good options to handle styles.

If you follow the instructions to convert your styles to Stylus everything will work fine.
Some minus - if you change the values of an existing style you use on userstyles there will be no changes made when you klick "update style". only uninstall and reinstall with new values works.
for this reason 4 stars.
would be nice if the develeoper would change this.