Ele deve funcionar com o Guia Mix Plus em. Ele vem com seu próprio gerenciador de sessões.
Tab Mix Plus (TMP) is a very popular
extension for the Mozilla Firefox
browser that enhances Firefox's tab
browsing capabilities. It includes
such features as duplicating tabs,
controlling tab focus, tab clicking
options, undo closed tabs and windows,
plus much more. It also includes a
full-featured Session Manager with
crash recovery that can save and
restore combinations of opened tabs
and windows.
Acho que, nas janelas com o conjunto predefinido de guias, você teria que usar o comando "Protect tab" (ou "Freeze" ou "Lock", clicando com o botão direito do mouse na guia) da guia você quer manter.
Protected tab: A tab that is prevented
from closing. You can load other sites
in the tab and browse to other URLs in
the tab. Notice that the close button
is missing from the right side of the
tab, so you cannot close the tab. If
you try to close Firefox, you will get
a warning message about closing the
protected tab.
Locked tab: A tab that is prevented
from navigating to another page or
URL. Your tab is locked on the current
page or URL. Nothing new can load in
the tab, but you can refresh the same
page. All links will open in a new tab
(link, history, bookmark, etc.).
Notice that the close button is
available, so you can close a locked
tab.
Frozen tab: A tab that is both locked
and protected. It will not close and
nothing new can be loaded in it. You
will not be able to navigate away from
the current page. All links will open
in a new tab (link, history, bookmark,
etc.) Notice that the close button is
missing from the right side of the
tab, so you cannot close the tab. If
you try to close Firefox, you will get
a warning message about closing the
protected tab.