Hello all,
I determined a different behaviour between OMV 2.2.13 and OMV 3.0.59 during a reboot while logged in to the GUI.
After the reboot in OMV 2 there is a big box with a message like "Software failure - Session not authorized". A short time later the login dialog appears. In OMV 3 I am immediately logged in to the GUI without any authorization request when I previously initiated the reboot within the GUI function.
Is it a bug or a feature? 
Greetings
cabrio_leo