Code for _get_property_list()

@tool
extends Node2D

var _open : bool = true:
	get: return _open
	set(value):
		_open = value
		notify_property_list_changed()

var _item_name : String = "default name":
	get: return _item_name
	set(value):
		_item_name = value
		notify_property_list_changed()
		
var _item_01 : InvItem = preload("res://inventory/items/item01.tres"):
	get: return _item_01
	set(value):
		_item_01 = value
		notify_property_list_changed()

var _item_02 : InvItem

func _get_property_list():
	var plist = []
	
	plist.append({
		"name" : "_open",
		"type" : TYPE_BOOL,
	})
	plist.append({
		"name" : "_item_name",
		"type" : TYPE_STRING,
	})
	plist.append({
		"name" : "_item_01",
		"type" : TYPE_OBJECT,
	})
	plist.append({
		"name" : "_item_02",
		"type" : TYPE_OBJECT,
	})
	
	return plist