Is the email message in Firefox, and that page is navigating to the linked page, or is the email message in a separate program, and it's launching the URL in the last active Firefox window? If the problem is an external link, could you check your setting for the following preference: (1) In a new tab, type or paste '''about:config''' in the address bar and press Enter. Click the button promising to be careful. (2) In the filter box, type or paste '''link.open''' and pause while the list is filtered. Then look for this and if its value is not 2, change it to 2. '''browser.link.open_newwindow.override.external''' -1 = open_newwindow applies to external links (<u>default</u>)<br> 3 = open external links in a new tab<br> 2 = open external links in a new window<br> 1 = open external links in active tab ''Edit: Probably a good idea to check this one, too, and set it to 2 or 3, as you prefer.'' '''browser.link.open_newwindow''' 3 = divert new window to a new tab (<u>default</u>) (checked*)<br> 2 = allow link to open a new window (unchecked*)<br> 1 = force new window into same tab '''*''' First checkbox in Options > Tabs ''(on Mac, Preferences > Tabs)''

Thanks jscher2000, This solved my problem.