I went a similar route but used an event instead of a transform and also incorporated recursion so that there could be a variable depth of child items in the menu:
I don’t have this in a production system yet, but wanted to throw it out there in case it helps anyone. Instead of binding to every item in the Horizontal Menu and Menu Tree, I wrote a couple scripts that rely on the menu onItemClicked event and the event.path property within that event. The event.path is a list of item indexes that leads to the selected item.
First I created a custom session property for holding the current selected path (this is my main menu, so it’s always visible and it c…