How do I enable pop up windows
For android application
They are disabled by default if I understand correctly, but there is currently not feature in the settings that gives the option to turn off or on at the moment.
Since it is case-by-case there are a couple of places that can "pop-up"
By default "<Firefox version> prevented this site from opening a pop-up window. Would you like to show it?" is shown by browser.popups.showPopupBlocker in about:config and is always set to true.
Do you have a website that is not showing popups? Can you please clarify with an example website with a pop up? Thank you.