By default WebClient can only maintain one WebClient session for the same browser, this causes that even if you open your WebClient application in multiple tabs, all of those tabs will share the same information, to change this you can use the WebClientMultiSession servlet that allow you create a different WebClient session for each tab you open in your browser.
Conditions:
to implement this servlet just follow these steps:
Define.WSACTION=/TestWeb/WebClientServlet
Define.WSACTION=/TestWeb/WebClientMultiSessionServlet