Introduction
In the bottom right-hand corner of the Firefox app, tap the menu button (hamburger icon). Tap Settings. Next to "Block Pop-up Windows", slide the toggle switch to the "off" position (to the left).
Instructions
1) In the bottom right-hand corner of the Firefox app, tap the menu button (hamburger icon).
2) Tap Settings.
3) Next to "Block Pop-up Windows", slide the toggle switch to the "off" position (to the left).
Outcome
Firefox will no longer block pop-up windows when you browse the web.