Rated 5 out of 5 stars

Great addon. However, i noticed that closing gmail and then opening google homepage tab sometimes does not clear gmail cookies and you have to log out from newly opened google homepage tab.

Edit: Thank you for the explanation. I'm changing the rating to 5 stars. Cheers.

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

This is expected behaviour with the default settings: everything under the google.com domain counts as one single cookie-consumer.

You can enforce stricter separation by activating the "Strict Cookie Access Policy" in the add-on's settings. That enforces the IETF cookie semantics and might help in this case. The drawback of this method is, that some sites might require whitelisting to make them work in this mode.