[arch-general] mouse freezes when switching between X sessions

If I have two X sessions running on different accounts and I switch between them (ctrl-alt-f1 ctrl-alt-f2) a few times. I usually get a frozen mouse in one of the two X sessions. I then must shutdown that X session and run it again (startx) to get my mouse working again in that account. Any ideas how to diagnose the issue, much appreciated. Thanks