Item Effect
Item Effect code controls what an item does when used in a dungeon. The table containing these can be found in Patches > ASM > Item Effects. Viewing this requires the ExtractItemCode patch.
Item Effects Tab
This is a table listing all items and the Effect IDs associated with them. Double-clicking the number next to the item name allows for editing the Effect ID number.
Effects Code Tab
This tab allows for adding/importing custom effects, as well as viewing a "filtered list" of which item(s) use each Effect ID. Adding custom effects that don’t exist in the base game requires ASM code.
Adding a new Effect ID is done by clicking the plus (+) button next to the Effect ID menu, which creates a new entry in the dropdown menu. Selecting it shows the “Used By” table is empty because no item is assigned to it when first created. Import the ASM code, then switch back to the Item Effects tab to assign the new Effect ID to an item.