Comment 7 for bug 1531913

yeah... I tend to agree that the fallback should be loaded if the specified artwork fails to load. if the scope returns a empty icon, that won't produce a failure. The dash can display what the scope requested just fine. No need for a fallback.

I totally get Rodney's point too, in the end it's probably a matter of preference. The more flexible approach to me seems to be what the dash currently does, allowing to specify no icon. Returning a 1x1 empty icon is certainly more of a hack.