I am the original author of the old Tab Mix. I am happy to introduce you another tab related extension: Tab Mix Lite. Feel free to leave you comment. If you want to REPORT BUGS, please go to:
Tab Mix Lite 4.0b1, compatible with Fx 4.0b2+, is now available for test. You can click the "view all versions" link to install it.
To keep this extension "lite", I am sorry that I could not accept feature requests. If you find this extension missing some features, you have several choices:
Tab Mix Plus, Tab Mix Lite CE, Tab Utilities, Tab Utilities Lite, Super Tab Mode, Tab Kit.