I wrote prior to the release of GraphWalker 3. So keep in mind the not all information in this article is valid for GW3. I'll make an updated version soon.
When modeling for a GUI of a system. It can be hard to find the best way for representing the modeled behavior on the system.
One have to think about haw to model what the tests interacts with. For bigger structures there are several approaches. Here are two approached, which are