Rated 5 out of 5 stars

Finally, after disabling all add-ons, I have reactivated all, one by one (or more precisely two by two) starting with ImageTweak and the bug has mysteriously disappeared! --- (I remind you what was the original problem: "since the last update (version 0.22), it is impossible to close the first tab") --- Now, there is no problem.

This review is for a previous version of the add-on (0.22.1-signed.1-signed). 

Rated 4 out of 5 stars

May 21, 2011 : This add-on is very useful, but since the last update (version 0.22), it is impossible to close the first tab. Can you fix this bug? Thank you. ----- May 24, 2011 : [Firefox 4.0.1 - Windows XP SP 3]. Finally, after disabling all add-ons, then have reactivated all, one by one (or more precisely two by two) starting with ImageTweak, the bug has mysteriously disappeared!

This review is for a previous version of the add-on (0.22.1-signed.1-signed). 

I can't reproduce the problem. Please test if it happens also with a clear profile with no other add-ons beside ImageTweak. If it still happens, please paste your UA signature (you can find it in about:support)