>I hibernated my notebook yesterday when UT's webpage opened. I opened my notebook today and I saw there isn't any timeout I'm still logon. If not wrong my mind, formerly there was a timeout. Isn't that a security lack?

There is no timeout on the site, nor was it ever at any time. So, doing that would make your Universal Thread session to remain available. All is ok in there. If you wish to force a logout, you can do it from the main page by the use of the upper right Logout option or by closing all windows of your browser.