Rated 4 out of 5 stars

Since yesterday I now only have a black oblong in place of the buttons in top right, still work okay, just cant see them...

This review is for a previous version of the add-on (2.24.1). 

Hi Richard, It has been fixed and new version has been submitted to Mozilla. Now it's in verification queue and it should be available in few hours.

Till then you may apply workaround:go to Preferences->Advanced tab->(button) Settings editor->type: "mail.tabs.drawInTitlebar" and set its value to "false"

or download fixed version form here:
https://addons.mozilla.org/thunderbird/downloads/file/228971/ms_office_2003_jb_edition-2.24.2-tb.xpi