Rated 4 out of 5 stars

This is a great add-on indeed! In fact I am only writing this to test it out so if this is spelt wrongly then its all you're fault!
it capitalizes the I in the beginning of the sentence but it doesn't capitalise other letters at the start of a sentence e..?
If I type something whilst the add-on is active (the icon is red) then if I click the icon again, the typed out text DISAPPEARS!!!?
That could be dodgy.
Hmm...one less star.

This review is for a previous version of the add-on (1.11). 

Please report bugs in the right place

Please report the disappearing text issue as a bug. When you report this as a bug (firefox@afterthedeadline.com is a good place to do so), don't forget to include the URL where you experienced this, the exact steps to reproduce it, your Firefox version and operating system. A list of add-ons you have installed helps too.