Use attribute alias in custom view window

[OimBeheer]

I want to configure a pop-up for a layer in my web map. So, I add expressions and give them een meaningful name as alias. But when I use these expressions in my custom attribute view (to customize the lay-out of my pup-up), the alias is not used. The result in de view is something like {expression/expr0}. I would be nice if the alias in used instead of this cryptic formula.