how to return to same browser window

Vaadin 6.7.3
Tomcat 7.0.16.0

My scenario is this:

I'm implementing an "I forgot my password" functionality which sends a confirmation email with a link, which when it is pressed, it requests a password reset and it sends another email back to the user with the new password

Because I use Vaadin fragments to signal the distinct request of password reset to the application, the link opens a new tab in Firefox.
I want it to open in the old tab, or focus on the old tab. The new request that opens in another tab shares the old still opened tab sessionid too

How do I form the link or what do I do so the new request is handled by the old tab?

This would be a browser feature and as far as I know it is not possible.

I agree that it's not possible, at least not in every case. It might work for you to try using a specific target name in the anchor tag, but I wouldn't trust it. The user could be using his non-default browser to view the site, so clicking the link in an email would bring up an entirely different browser. You're out of luck there.

I would hope that users are used to this behavior by now, closing the old window once the email arrives.

Cheers,
Bobby