For the second time in two days, my mouse just "disappeared" from my desktop system running CentOS 4.1 (yes, I'm using CentOS as a workstation). At the time, I was trying to open the main Gnome menu from the panel, and I think my hand slipped before I released the mouse button. I tried accessing an alternate console (Ctrl-Alt-1) and then coming back to the X11 desktop (Alt-F7) but that didn't fix the problem. Alt-Tab wouldn't cycle through windows, and when I tried to do a xkill from the active xterm window, I got a "Can't grab the mouse" error.
I killed the X server with Ctrl-Alt-Backspace and logged back in, and everything is back to normal. Has anyone else seen this? Any suggestions on how to debug this next time it happens?
To be fair, I should tell you that I am using Synergy (http://synergy2.sourceforge.net) to share the mouse and keyboard of the CentOS system with two other systems (my CentOS box is the Synergy server). I've been using Synergy for a long time, and CentOS almost as long, and have never had this problem until this week.
My last yum update was on 9/17 and it did update the xorg-x11 packages. I wonder if this is a bug in the latest release...
Alfred