No New Window on Double Click 0.1
Currently, upon double-clicking a folder in the folder-pane in Mozilla Thunderbird a new instance of the email client opens. This feature — dare I say bug — has haunted me since my move from Outlook Express. (I've whined about the default behavior since July 2003.)
Great news — there is now a fix: The No New Window on Double Click extension (right-click to save). Instead of opening another window, the plugin will collapse or expand folders which have subfolders. If you have any comments for the extension's author navigate to this thread at the MozillaZine Forums.