Hello,
I have the impression that there is a different behavior between admin and user portal when opening a VM console with remote-viewer.
My client is an updated CentOS 7 machine and I'm using firefox on it to connect to oVirt 4.0.4 portals.
If I connect to a VM (that is a Fedora 24 os) from web admin it runs remote-viewer.
I switch to full screen mode and leave it some hours.
When I come back I see a black screen and I'm not able to re-get the session.
I can click on top center to pop up the menu and exit the remote-viewer full screen but also in window mode I'm not able to get again the desktop environment inside the VM (I configured Mate desktop in fedora 24 VM): it remains black window. The VM itsel is ok: I can close the remote-viewer window and open again the console and I get the desktop environment.

Instead from User Portal on the same client I can open the console (again remote-viewer), leave the session in full screen mode and come back many hours later and as soon as I click or press a key I get the session ok (sometimes actually I get the screen saver locked of the client desktop environment itself, but as soon as I unlock it I can connec thent to the VM desktop).

Any special reason for this?

In both cases the command seems the same:

admin portal:
 $ ps -ef|grep remote-viewer
g.cecchi 10356  9462  0 18:59 pts/1    00:00:00 grep --color=auto remote-viewer
g.cecchi 16814 20129  0 01:30 ?        00:00:54 /usr/bin/remote-viewer /tmp/mozilla_g.cecchi0/console.vv

user portal (extended mode)
$ ps -ef|grep remote-viewer
g.cecchi 11544 20129  0 19:02 ?        00:01:18 /usr/bin/remote-viewer /tmp/mozilla_g.cecchi0/console.vv
g.cecchi 23534  9462  0 22:54 pts/1    00:00:00 grep --color=auto remote-viewer

Not a big problem, but quite strange.

Gianluca