I have the exact opposite problem. I am using asp.net. What I am experiencing is my asp.net membership provider (which is a custom Amazon dll) will allow user 2 on tab N to be authenticated but then when the code hits the first page of my website it reverts to user 1 who is still active. In the debugger I see the sessionid values changing like mad. I use crazy async ajax calls but franky this is driving me mad so to remedy I started using a custom cookie to track the first successful login thereby limiting my browser to one user at a time. However in Chrome 12 each tab has a potential different value. My login page forces no caching but even when I watch the javascript delete the cookie it is alive in other tabs. Thus I have no way to synchronize behavior. I am trying to shield the user from this complexity, and even more annoying this is a corner case but people freak over cookies and logins so I cannot figure this out. I tried testing to simultaneous yahoo logins and they can track when one user logs out and the other tabs will say, "your session is no longer active" So I cannot get a handle on the active user, if they have logged out, etc. between tabs/windows for the same browser & I have read and read and never had issues with cookies before but this behavior seems odd to me that you cannot force one browser-wide global cookie for tracking this kind of stuff. My cookie is set to "/" path so after reading and reading it is just maddening. And on top of that Firefox 6 does not delete the cookie when browser closes even though the expiration is the default of 0, i.e. kill coookie when browser is closed. I am just shaking my head in disbelief at this sad state of event on what seems so primary a task to my addled brain. Sigh....