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CloseReview for Compact Menu 2 by Firefox user a67dda
Rated 4 out of 5 stars
Very useful to save screen space especially since AFAIK, this is the only one of it's kind that works on Thunderbird.
Just a small "problem": on TB3 the button is wider than on TB2. I suppose this is because by default, it should have the label beside it just like all the other buttons.
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