e.g.

Tasking::GroupItem runRecipe()
{
    ....
    .... Tr::tr("something") ....
    ....
}

results in "Qualifying with unknown namespace/class ::Tasking".
Even fully qualifying the Tr::tr call doesn't help. What helps, is to declare a "using GroupItem = Tasking::GroupItem;" and using just "GroupItem" as the return type.