#1172 close all sessions doesn't close all sessions

[mkls]

when I have more session to different databases open and right-click on one of them and select "Close all session" then only some of the session are closed. It seems that squirrelsql starts closing sessions randomly and when it hits problem then it stops closing them. I've also noticed that it is trying to close session that are not open anymore - in which case will not close any sessions.