Sorry to be the one to say (again!!) @BartButenaers but it's not working here.. 
I've configured the node as per the readme, using a simple fixed menu, but it does not appear in the dashboard group.
Checking my browser console, I see the following;
If I try and load https://nodered.digitalnut.co.uk:8443/ui/ui_context_menu/contextmenu.js?_=1582707759368 in a browser (as per the 401 error above) I get a prompt for auth. If I enter my user/password, then the contents of this file is then displayed.
The same applies with https://nodered.digitalnut.co.uk:8443/ui/ui_context_menu/contextmenu.css, again I'm prompted for auth.
I'm assuming that this is because I've password protected the Node-RED editor, admin API & the node-defined HTTP endpoints using adminAuth & httpNodeAuth (remember we had similar issues with node-red-contrib-xterm).
