Option "-lastsession" doesn't work

I have downloaded a nightly build of qt creator (2.2.84, August 10, 2011). The executable is located under ~/qtcreator-2.2.84/bin. I navigated there (in a terminal), and then typed "./qtcreator -lastsession", which starts creator, but doesn't restore the last session, as it's supposed to do according to the help page.