There's a good chance this is related to a bug that kicks in when you do not have Flash running in any tab and you open a new window to a page that does use Flash. The details and known workarounds are in this thread: Opening New Windows and Shockwave Flash.

Try Firefox Options > Tabs.> When I Open........ While this says tabs, maybe this can help. When I call for a new window, I get moved to the new window.

I've determined that it's Schockwave Flash that's causing this on my computer. As long as I disable that plugin, when I launch a new window, it doesn't revert to the original window.

But then, of course, I can't watch most videos online. C'mon Adobe and Mozilla. Get it together and fix this problem!

And it happens when opening windows to most pages (almost always, not not every single time), not just ones that use Flash.

Does this pref (about:config) have any effect: dom.disable_window_flip ?

Thanks for the suggestions. I don't want to try it, but I'd be really interested in hearing from others who've tried the dom.disable_window_flip method of dealing with this enervating problem.

Meant to insert a comment regarding flash suggestion, but put it here by mistake.

I have no idea what you are referring to or how to impliment what you are mentioning. If you can explain how to try it for a non-techie, I'd certainly be interested and grateful.

Same with me, flash solution does not solve the problem.

FYI, this is not a threaded forum, so all replies appear at the bottom...

dom.disable_window_flip is a true/false preference that determines whether a script in a web page is allowed to change focus between Firefox windows (typically, bring itself to the front, or pop-under by bringing the window from which it was opened to the front).

By default, this preference is set to true to disable websites from moving windows around, but it's possible that setting was changed. To view/change this preference, you can use the about:config preferences editor.

(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 search box that appears above the list, type or paste flip and pause while the list is filtered

(3) Double-click dom.disable_window_flip to switch it between true and false.

Edit: Corrected per the post below.

Jscher

Your solution worked, thanks! I had some difficulty deciphering what you meant me to do, but figured it out.

For anyone else who wants to use your solution, in step 2, "the filter box" is the place near the top of the screen where you search for a term you want to find in the long list below.

I've further determined that Facebook has something to do with this mess, surprise, surprise. Altering the flip config did the trick (thank you, jscher2000) for all but Facebook links. Hmm. More mystery.

dom.disable_window_flip change didn't work for me. Also I have the latest versions of java, Schockwave, Flash installed. I use the Firefox 24 on a Windows 8.1 OS.

Update: I have just updated to Firefox 25. Same problem: Firefox is going back to the previous window, as soon as I click on a link to open a new window. The new window still opens but the focus is turned to the previous one. This is just frustrating. So Mozilla has done nothing to resolve this problem so far. Note that I don't use tabs. I have chosen to open links in new browser windows instead.

Hi pan-firefox, did you just update to Windows 8.1? How is that going in general?

The change of window focus could be a problem with the protected mode of the Flash Player plugin. Could you check the following thread and see whether that helps: Opening New Windows and Shockwave Flash.

Sadly, I tried the keeping-a-Shockwave-page-open method awhile ago, but it didn't work. I'll try disabling Shockwave. Thanks for the suggestions!

Disabling Shockwave's protected mode did the trick. Apparently, my system's security is a bit lessened, but the flipping between windows was making me about ready to smash my computer, so my laptop is actually safer.

Hahahaha

I disabled flash protected mode and the problem seems to have been solved. Please hackers don't attack my PC now, OK?

PS. Windows 8.1 upgrade from 8.0 went smoothly. I didn't notice any difference from the previous version though. I also had a minor problem with the desktop wallpaper which was lost after the update.