I like Firefox 3.0, particularly for its speed and Awesome Bar.  However, I do not like the fact that all the bookmarks in my Bookmarks Toolbar open up in the current tab.  I want them to open in a new tab.  I used the Tab Mix Plus extension to accomplish this in Firefox 2.x, but that extension isn’t compatible with 3.0.  Today Google helped me find a (mildly involved, but not too terribly difficult) fix for that problem.

1. Download and install UserChrome extension: http://mozilla.zeniko.ch/userchrome.js.xpi – this will allow Firefox to open/run the next files.
2. Restart Firefox.
3. Copy two JavaScript files (userChrome.js and OpenInTab.uc.js) into your Firefox chrome folder.  See path below:
   C:\Documents and Settings\[Windows login/user name]\Application Data\Mozilla\Firefox\Profiles\[profile folder]\chrome
4. When you copy the files, a dialog box will ask you about replacing the existing userChrome.js file – yes, you need to replace it.
5. Restart Firefox.

Now all your bookmarks (in the menu or in the bookmarks toolbar) should open in new tabs.

One caveat: a comment on the original page claimed that this doesn’t work on Mac OS X, but I haven’t tried on my MacBook yet – I’ll try that tonight or tomorrow.