Firefox diverts most new windows to tabs, but there is an exception when a website uses a script to specify the window's dimensions or removes some toolbars. To remove the exception, you can make a change under the covers. This could be awkward for genuine dialog windows that don't make sense to view in a separate tab, but if you find it more annoying than useful, you can easily switch back.

(1) In a new tab, type or paste about:config in the address bar and press Enter. Click the button promising to be careful.

(3) Confirm that the browser.link.open_newwindow preference is set to its default value of 3 (divert new windows to a tab instead), or right-click > Reset to get that value

(4) Double-click the browser.link.open_newwindow.restriction preference and change the value from 2 to 0 (that's a zero) and click OK

Any luck?

For future reference, the possible values for the window/tab preferences are:

(A) browser.link.open_newwindow

3 = divert new window to a new tab (default) (checked*) 2 = allow link to open a new window (unchecked*) 1 = force new window into same tab

* First checkbox in Options > Tabs

(B) browser.link.open_newwindow.restriction - for links in Firefox tabs

0 = apply the setting under (A) to ALL new windows (even script windows) 2 = apply the setting under (A) to normal windows, but NOT to script windows with features (default) 1 = override the setting under (A) and always use new windows

(C) browser.link.open_newwindow.override.external - for links in other programs

-1 = apply the setting under (A) to external links (default) 3 = open external links in a new tab in the last active window 2 = open external links in a new window 1 = open external links in the last active tab replacing the current page

I should add that with the above change and your current settings, you would need to Shift+click links to launch a new window instead of a new tab.

I noticed you have a number of add-ons that others have considered annoying hijackers. If you are getting unexpected advertising or intrusive pages, here is my recommended clean-up procedure:

(1) Open the Windows Control Panel, Uninstall a Program. After the list loads, click the "Installed on" column heading to group the infections, I mean, additions, by date. This can help in smoking out undisclosed bundle items that snuck in with some software you agreed to install. Take out as much trash as possible here.

(2) Then, in Firefox, open the Add-ons page using either:

• Ctrl+Shift+a
• "3-bar" menu button (or Tools menu) > Add-ons

In the left column, click Plugins. Set nonessential and unrecognized plugins to "Never Activate".

In the left column, click Extensions. Then, if in doubt, disable (or Remove, if possible) unrecognized and unwanted extensions.

Often a link will appear above at least one disabled extension to restart Firefox. You can complete your work on the tab and click one of the links as the last step.

(3) Mop up remaining issues with the scanning/cleaning tools listed in our support article: Troubleshoot Firefox issues caused by malware.