Interesting. I had a similar problem yesterday. I was watching some television shows and waiting for my babies to grow up. I put the screensaver on. During the show, the research finished, and then I couldn't even click anywhere. The computer wasn't frozen, and I suspect that I could have returned to normal operations if I'd been able to land my mouse pointer on the 'ok' button on the research completed notification screen. Unfortunately, in the screensaver mode, the mouse pointer can't be seen.

After five minutes of trying to land the stupid thing on the button, I just shut down my computer and re-booted it up. When I checked my games, everything was normal again. I guess it's just a bug with the screensaver mode and only happens with research completed notifications.

Rainbowfish