I Googled for "Websphere same client same session tracking" and got this:
http://publib.boulder.ibm.com/infocenter/wasinfo/v5r1//index.jsp?topic=/com.ibm.websphere.zseries.doc/info/zseries/ae/rtrb_httpsessprobs.html See the "Session is shared across multiple browsers on same client machine" section.
According to them it's completely browser dependent but I'm not so sure that's a good enough explanation. If you had different jsessionids,
you should be getting different sessions. Each new browser instance (as opposed to window) should start afresh. Perhaps IE (being basically an integral part of the OS) is inconsistent in this respect?
My only other question would be are you sure your pages aren't being cached? It is possible that the first browser is showing you one session ID (presumably from a
JSP output or something) and when loading the second you are seeing the same original page pulled from the cache rather than a new, updated, version. You can try refreshing the page several times to make sure any cached version is cleared, or add this to your JSP:
which will prevent IE from caching your page.
Please let us know how you get on and if you find a solution (or indeed caching is the problem)...
Charles Lyons (SCJP 1.4, April 2003; SCJP 5, Dec 2006; SCWCD 1.4b, April 2004)
Author of OCEJWCD Study Companion for Oracle Exam 1Z0-899 (ISBN 0955160340 / Amazon Amazon UK )