While being logged in, watching the container list, or the dashboard (probably doesn't matter which page is opened) after 5 minutes the hawt.io will open the login page again, seeing in the logs

"2014-10-12 04:26:05,155 | INFO | p1006754543-5145 | SessionExpiryFilter | io.hawt.web.SessionExpiryFilter 122 | 121 - io.hawt.hawtio-web - 1.2.0.redhat-403 | Expiring session due to inactivity"

I am not sure what "activity" needs to be done to reset the session expiry, but having the window opened while watching the dashboard should definitely be considered as "activity".

Update: this does not depend on the "remember me" setting.