Tree Style Tab structure not preserved in saved sessions.

[Napoleon-BlownApart]

When using Tree Style Tab, sometimes, quite often, saved sessions do not retain the folder structures of my tabs.
As a result, almost all the tabs end up being root nodes and, short of manually recreating the structures, the organisation of my tabs is demolished.
This has been a problem for some time, but now I've run out of back-up saved sessions to fall-back to.

[Napoleon-BlownApart]

In addition to the above problem, I've noticed that sometimes tabs are not recorded in the snapshot.
Getting back to my browsing session after a reboot etc. is sometimes a bit frustrating.