You still need to set the app as default. M$ do all they can to force you to use their apps and not 3rd party stuff.
I know, i looked for it in the apps and it was not there. But now it is, very strange, I even rebooted the machine, but it was still not visible, but I just had another look and it is there.
It is not third party it is Ms own software, just an older one and not horrid universal rubbish. you are right Ms will try anything to get us to use rubbish Windows 10 apps. If I can get windows 8 working on this machine i will go back to that.
Desktop machine now powered by windows 10 pro, reluctantly, laptop by Linux