To add an game to the Favorites you should be able to go to the game you want to add from Recent ( for example ) and then alongside Run, Rename and Remove you should be able to “Add to Favorites”! It would be alot more convienient this way instead of having to run the content first and then go to Quick Menu and then add to favorites from there!
I could make an mockup if you really wanted!
I see this option has been added but it doesn’t work.
I know right, it’s exactly what I wanted but it also doesn’t work for me.
I just tried the nightly and the problem still seems to exist. 
I want this option works too, because I’ve a lot of emulator games and is the best to have the favourites in just one place.
Now that this option is here can games be added to the end of the list instead of beginning? I know I can edit the list in wordpad.