Some sites are annoying -- we shouldn't overlook the possibility that this is their way of monetizing you. If there are particular sites that cause this problem that you want to post the addresses of, a volunteer could take a look.

But another possible culprit would be an extension. You can view, disable, and often remove unwanted or unknown extensions on the Add-ons page. Either:

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

In the left column, click Extensions. Then cast a critical eye over the list on the right side. All extensions are optional. If in doubt, disable.

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.

Any improvement?

Dear jscher2000, thanks for the quick response, unfortunatelly this doesn't seems to be the "problem" since every extension I have is there on purpose and so far didn't caused any trouble. I also suspect this is a move from the website's side, I just don't know where to turn for help blocking those few lines of code on my side...

Can you provide links to pages on the problem sites where you experience this problem?

You also could experiment with different popup and script blockers, although I have no idea whether those would help.

The only concrete example I can recall at the moment is Pirate Bay, but it happened on various blogs and online magazines too. I will get back with links if I run into them again, until then, thanks for the suggestions!

It's a deliberately deceptive tactic and made to be purposely hidden behind your main active window. Can't imagine these methods are actually helping sales but whatever, FF still has tools to fight this kind of shit.

Set these entries to "true":

• dom.disable_window_open_feature.location
• dom.disable_window_move_resize

DOM is what's responsible for websites getting in there and messing with your expectations of what's standard in the browser interface like hiding your mouse cursor, not letting you close a window, hiding pop-ups behind other elements, etc. You can set all of the "dom.disable_window_open_feature.xxx" options to true if you want. It will help to keep websites from doing stupid, irritating things.

Next, check these:

• browser.link.open_newwindow
• browser.link.open_newwindow.override.external
• browser.link.open_newwindow.restriction

These dictate where any new windows will open. Most people like new windows to open as new tabs and always having new windows open as new tabs also removes the possibility of any pop-up hiding behind your main browser window.

My personal settings for these are listed below. They ensure if any pop-ups manage to get through they are forced to open in a new tab and not in an new window.

• browser.link.open_newwindow = 3
• browser.link.open_newwindow.override.external = -1
• browser.link.open_newwindow.restriction = 0

Thank you proxy.socks, I set up the recommended values and so far they are working (not that I had too much time since then to roam around the interwebz, but hey, it's a start...) I appreciate your help!

I have been using this code in a user.js file for over 10 years now, to stop websites from messing with the various " window_open " features in Firefox.

// advanced JavaScript Options: user_pref("dom.disable_window_move_resize", true); user_pref("dom.disable_window_open_feature.directories", true); user_pref("dom.disable_window_open_feature.menubar", true); user_pref("dom.disable_window_open_feature.personalbar", true); user_pref("dom.disable_window_open_feature.scrollbars", true); user_pref("dom.disable_window_open_feature.toolbar", true);

By using the user.js file I don't have to remember to set these prefs every time I create a new Profile; just place a copy of that file in a new Profile and I'm "good to go". Plus I have a couple of dozen other preferences in user.js, too. Anything in about:config can be added to user.js, including prefs for your most used extensions. http://kb.mozillazine.org/User.js_file