Using built in icons for dashboards

Ok, another question:

There are the font awesome icons and the Material Design ones.

I've opened the Material Design page and using some of those for the list on the left of the dashboard screen.

Some work, some don't, and I don't know why.

See picture.

I know it is going to be difficult to work out, but the two RED ones:


Only the original set are baked into Node-RED for offline use -
BUT you can use the others if you specify them like mi-videogame_asset (ie add an mi- to the front of the name) and your device has access to the internet.