Rated 5 out of 5 stars
Well its not working for version 39, and so on. But who needs this extension, you have to edit it. And works fine. How to edit : http://kb.mozillazine.org/Editing_an_add-on_to_change_its_compatibility
You have to change 3 files. Put 46.* for example. Be careful in the all operation of renaming files etc.
Please note that, in contrast to this review, Ignore Aero does have some major bugs in current versions of Thunderbird (for example in the toolbar for HTML formatting). I thus intentionally did not mark the theme as compatible with TB 45. If you can live with these bugs, that's great – you're welcome to bump the theme's compatibility if you want to :)