Lestat, what you are describing is the original, complicated, version of digging.
Going back to AT LEAST AoS (when I started playing), the t-maps have a context menu, that allows you to select to dig for the map with all that extra clicking.
You click on the map to bring up its context menu, you select "Dig for Treasure" and target the ground where you want to dig. That's it.
I didn't know the way you describe existed until I'd been the GM of my local THB for several years, having learned to do it the other way.
Typically, the grayed-out "Dig for Treasure" means that you don't have any digging tools in your pack or equipped.