Open jupyterlab in Firefox app mode

anyone using Firefox app mode?

Any ideas why this wouldn’t work with local host domains being passed from the commandline? trying to use if for jupyter notebooks ?

How to "Use This Site in App Mode" in Firefox v77

Firefox Use This Site in App Mode

Use This Site in App Mode feature lets users run any website in its own window with minimal UI. The web page with the feature will open up with no navigation controls or no toolbars, but won’t open up in full screen mode, gives you a feeling that you’re using a desktop application.