Review for Hide C. Titlebar Plus Lite by Zitronius
Rated 4 out of 5 stars
This add-on helps well to make Thunderbird looking better. But Thunderbird 31.3 appears still bullheaded: if in about:config the item "mail.tabs.autoHide" is set to true the titlebar is still there. And with "mail.tabs.autoHide" set to false there is still an empty useless annoying blue bar in the unmaximized window under the topmost bar.
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