Could be your test malfunctioning in some way. Doing multiple things at the same time is complicated.
I wouldn't immediately rule out the application you're testing, though. Funny story, a few years ago I was working for a large company that was developing a new web application. So they worked on this thing for months and it was going great. All the testing looked great. Then they did a live test and had all sorts of problems with users getting each others' sessions. Turns out all their authentication was using static java methods to do almost everything, the end result of which was you actually could only have a single session. If you tried to have more than that, they'd overwrite each other in unpredictable ways. -- Bruce Ide flyingrhenqu...@gmail.com