In Episode 05 of my Ultra Modular Interaction and Inventory System series for UE 5.4, I start by cleaning up a couple bugs that kept popping up in the community. The big one is drag-and-drop: if you drop an item on itself, weird stuff happens because we never defined that scenario. So I add a simple “cancel drag” boolean, check whether the source container + index matches the target container + index, and if it’s the same slot I just cancel the operation so it behaves like nothing happened. After that, I fix a mistake in my “remove item from inventory” logic. I was searching by tag and grabbing the first matching stack—which breaks the second you have multiple stacks of the same item. The fix is to route the index through the UI and validate/get the item by index instead of relying on tag lookup. From there I start building the actual item blueprint hierarchy (materials, consumables, tools, melee weapons, storage, production) and set up a new way to attach auxiliary item data, like a consumable Primary Data Asset, without forcing casts everywhere. Finally, I migrate my G.A.S-inspired Blueprint Ability System into this project (on purpose, so I keep a reusable generic version elsewhere), recreate the gameplay tags, and begin wiring “try interact” and “try consume” as montage-based abilities with proper state tags and events.