Opera tab groups in Firefox 4 Beta?

Question

I realize Firefox 4 is still beta, but I'm wondering if anyone knows of an addon which will allow you to group tabs as in Opera's tab "stacking". I find this much nicer than Firefox's tab "groups".

For more details, see this link.

Answer 1

Using the PRE version of Tab Utilies you can do this.

Some of the settings are hidden though, and you need to go into about:config and then in the filter bar type in extensions.tabutilities. and you will find in there settings for the stacking and auto-stacking.