Comment 49 for bug 68370

I have discovered new and important information about this bug.

It seems that the bug is triggered whenever a window in the other/old session steals focus. This explains why locking the first session before running switch user is a workaround. In that case the focus has been grabbed before the new session starts so the new session does have mouse control.

I discovered this when my wife told me the computer had crashed - it hadn't crashed, just the mouse wasn't working. When I switched to my VT there was an error dialog box waiting for me to click "Okay".

It is possible to verify this behavior by running "sleep 10 && zenity --error" in one session and switching to another session. Using a longer sleep time may be easier for you.

Please verify this conclusion if you can. We should revise the description if it's correct.