It sounds a bit weird, but once you read below you'll see how it makes sense.

GroupWise 2012sp1 webaccess behind NetIQ Access Manager, configured with FormFill. The users login fine, the SSO works fine, and the logout url in webacc.cfg is changed to /AGLogout of the AccessGate URL. However, once you're in and you open a Proxy to another mailbox, the proxy opens in a new browser window. So far so good. Once you finish working with the proxy, even though you closed the browser from the X button (not the logout link), your main session with the AccessGateway is cleared as well and you need to re-login in the main webaccess browser window. If I comment out the logout url setting in webacc.cfg, then if I close the Proxy window all is fine (I can still work in the main webaccess browser window), but I cannot logout from GroupWise webaccess, as the logout redirects to the login page and the formfill kicks in and I'm logged-in again in webaccess.

Is it possible to tweak webaccess in a way that when closing the browser it doesn't perform the custom logout?