I'm seeing this too on Utopic quite regularly. For me, it happens when I use the icon in the task switcher to get an overview of the four workspaces. When things freeze, I see the four workspaces filling the screen, with the shrunk windows in each workspace, and no more response at that point. Sometimes, hitting Super-S gets things back, other times it doesn't.
I'm seeing this too on Utopic quite regularly. For me, it happens when I use the icon in the task switcher to get an overview of the four workspaces. When things freeze, I see the four workspaces filling the screen, with the shrunk windows in each workspace, and no more response at that point. Sometimes, hitting Super-S gets things back, other times it doesn't.