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CloseReview for MinimizeToTray by sberg43
Rated 5 out of 5 stars
I too was unable to use this add-on after the update to Thunderbird 3.1.2. A nice replacement is "MinimizeToTray revived"
https://addons.mozilla.org/en-US/thunderbird/addon/12581/
(My rating is for the new add-on)
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