Rated 5 out of 5 stars

Excellent! I've been hacking the UI a lot. This is essential to me.

I've used it to get rid of the Windows-supplied title bar and have added my own to several of the Thunderbird Windows &amp;amp; Dialogs, like how tabs-in-titlebar (Advanced Preferences: "browser.tabs.inTitlebar" (oops! Is that "mail.tabs.drawInTitlebar" instead???), <body> tag attribute "tabsintitlebar") work in the main Window.

Enhancement Idea:
- add more Window/Dialog types - I hacked this extension to add filterListDialog and FilterEditor. Perhaps more coming.

Can you submit a pull request for your changes at https://github.com/Extended-Thunder/userChromeJS ?