Action RPG Inventory System

I’ve worked at this for a week or so but have not been able to come up with an answer.

The value reported by the length node, the tooltip of which says “Get the number of items in an array.”, always shows zero for the Inventory Item Array in the editor.

The inventory is working properly in game.

I know that I can get a hack number by adding the number of Equipment slots to the number of backpack slots and use that as an iterator, but how can I programmatically derive the number of slots in the Inventory Item Array?