Edge works for me (I don’t have FF to test). But until you describe in more detail, I am quite confident there isn’t a bug, because that’s a highly-used feature of Notepad++, and it would surprise me if there were a fundamental bug that you were the first to notice.
Could you be more specific? You claim there’s “different issues” but don’t explain what they are.
Share your ?-menu’s Debug Info What are the issues? Does it not show at all? Are you just talking about the HTML doesn’t render as you expect? Because that has nothing to do with Notepad++, and we cannot help you with HTML. (The best way to tell if this isn’t the right place: if writing the exact same HTML code in notepad.exe gives you the same “different issues” in FF and Edge that writing it in Notepad++ did, then the problem is not with Notepad++, and instead it’s with your code.) How is it different between FF and Edge? What’s the filename you are opening? Viewing in the browser is obviously intended for HTML and similar static web technologies Are the changes to the file not yet saved (or is the file an unsaved new # file)? Because if you have made edits to your file, but not saved them, then what you see in FF/Edge will be what you last saved, not what’s currently showing in Notepad++. And if you don’t have any underlying file and are just looking at an unsaved new # file, Notepad++ cannot tell the browser to look at file XYZ because there is no file for it to point to.