OK, you session crashed. Do you keep clicking the Restore session button? If so, it keeps restoring the crashed session.
You really need to find out why it's crashing. If it's the way you close the browser, you should change it and exit the proper way: File/Exit. If you have an ext. that crashes your browser, you need to find that ext.
I'd suggest you reinstall TMP - the latest dev.build (link in my signature):
1. uninstall TMP
2. type about:config
in the url bar/enter
3. in the Filter field type tabmix
4. right click on every line that will show/Reset
5. exit Fx
6. go to your profile
(< link) and delete sessions.rdf file
7. start Fx
8. install TMP dev.build (link in my signature)
9. restart and see if the popup shows
EDIT: if you want a single click exit, install the Exit button from here
, it installs a small extension.