Normally, when a link in a page in Firefox directs Firefox to launch it in a new window, Firefox diverts it to a new tab instead. There is a checkbox on the Settings page for that. To check on it, open the Settings page and read down to the third or fourth section ("Tabs"). Make sure the box is checked for: [x] Open links in tabs instead of new windows Is that turned on? Sometimes the link calls a script that specifies the new window should have particular features, and you get a limited feature pop-up window where you can't edit the address bar. There is a hidden setting to force those into a tag as well. I'm going to point you to a test page on my website for more details: https://www.jeffersonscher.com/res/popit.html Finally, links you launch outside of Firefox (for example, in Microsoft 365 apps or in Acrobat) can open either in a new tab or a new window based on ''another'' hidden setting. If the problem is with external links, please let us know for more information about those.