It's expected behavior when a session is cookie based. Cookie it's something hidden for you browser sends to server and
servlet container uses it to maintain session. If you would like to keep session copying URL from address bar of one browser to an address bar of other browser, then you can try to use session based on URL overwrite mechanism. Check your servlet container
doc how to enable it. In this case URL will include session token and you can continue work on other instance of a browser.
Tough in space?, <a href="http://tjws.sf.net" target="_blank" rel="nofollow">Get J2EE servlet container under 150Kbytes here</a><br />Love your iPod and want it anywhere?<a href="http://mediachest.sf.net" target="_blank" rel="nofollow">Check it here.</a><br /><a href="http://7bee.j2ee.us/book/Generics%20in%20JDK%201.5.html" target="_blank" rel="nofollow">Curious about generic in Java?</a><br /><a href="http://7bee.j2ee.us/bee/index-bee.html" target="_blank" rel="nofollow">Hate ant? Use bee.</a><br /><a href="http://7bee.j2ee.us/addressbook/" target="_blank" rel="nofollow">Need contacts anywhere?</a><br /><a href="http://searchdir.sourceforge.net/" target="_blank" rel="nofollow">How to promote your business with a search engine</a>