Hi,
As Ori mentioned, Visual WebGui cannot cause this phenomenon by infrastructure, as interacting from one IIS session object to another practically means hacking IIS and ASP.NET.
I suspect that you have some false business logic which has the power to switch between the active users somehow, however, there is no chance we will be able to truly validate that you without a working sample. I truly understand that you can't possibly send the app over, but since you think it's a VWG phenomenon, it should be possible to create some kind of small app reproducing this issue.
A couple of applicative hints I can think of:
1. Try to think of your logon mechanism, where exactly in your code the logon process is performed? could this code be invoked in other then logon cases? Do you use VWG form logon? Windows Authentication SSO? or you have built your own mechanism?
2. Do you have some code within ASP.NET Session_OnEnd procedure?
3. Have you been using timers? in case you did, can the code there cause switching users/logon/logoff?
4. Have you been using threads? Note that IIS threads are limited and are unsafe unless synchronized programmatically.
5. Have you been using COM or other interoperated non .NET components? can this be the reason for threads in safety?
One information piece I find very important, do you know if the other user that the app happened to switch to was logged on to the system at the same time the users were switched?
I hope this helps...
Kind Regards,
Itzik Spitzen