Functionality when freshly installed

[simonrepp]

Thanks for css-reloader, this is a great tool! 🎉

One small remark/suggestion I'd like to make:
I just installed it for the first time and tried reloading the css on a page that was already loaded before I installed the addon (in firefox by the way) - this did not work. However luckily I gave it another attempt after freshly loading the page and then reloading the css and that worked then.

If this is a known limitation and can't be avoided I would maybe add a small note to the usage section on the add-on page. If css-reloader can be made to work even in the above described scenario all the better! :)

Thank you, keep up the good work! 👍