How to Disable a Pop-Up Blocker on Firefoxby Andrea Reuter ; Updated September 28, 2017
The Mozilla Firefox browser includes a pop-up blocker that prevents websites from opening new windows without your permission. With the blocker enabled, you receive a notification from Firefox whenever a website tries to open a new window, and you're given the option to open the window manually or ignore it. Pop-up windows are integral to the function of some websites, like online gaming sites and financial institution websites, making it necessary to temporarily disable the Firefox pop-up blocker.
Select "Tools" from the top of your Firefox window.
Choose "Options" from the drop-down menu.
Select the "Content" tab.
Uncheck the box next to "Block pop-up windows" to disable this feature.
Press the "OK" button at the bottom of the "Options" window.