private void DrawItem(int index)
        {
            CollectableScriptableObject collectionItem = filteredItemList[index];

            using (new EditorGUILayout.VerticalScope("Box"))
            {
                using (new EditorGUILayout.HorizontalScope())
                {
                    CollectionUtility.SetFoldoutOpen(collectionItem,
                                                     EditorGUILayout.Toggle(GUIContent.none, CollectionUtility.IsFoldoutOpen(collectionItem), EditorStyles.foldout,
                                                                            GUILayout.Width(13)));

                    using (EditorGUI.ChangeCheckScope changeCheck = new EditorGUI.ChangeCheckScope())
                    {
                        string newName = EditorGUILayout.DelayedTextField(collectionItem.name, CollectionEditorGUI.ItemNameStyle,
                                                                          GUILayout.ExpandWidth(true));

                        if (changeCheck.changed)
                        {
                            AssetDatabaseUtils.RenameAsset(collectionItem, newName);
                        }
                    }

                    DrawSelectItem(collectionItem);
                    DrawMoveItemDownButton(collectionItem);
                    DrawMoveItemUpButton(collectionItem);
                    DrawDeleteButton(collectionItem);
                }

                if (CollectionUtility.IsFoldoutOpen(collectionItem))
                {
                    EditorGUI.indentLevel++;
                    Editor editor = CollectionUtility.GetEditorForItem(collectionItem);
                    using (EditorGUI.ChangeCheckScope changeCheck = new EditorGUI.ChangeCheckScope())
                    {
                        GUILayout.Space(10);
                        editor.OnInspectorGUI();
                        EditorGUILayout.Space();

                        if (changeCheck.changed)
                        {
                            if (index > filteredSerializedList.Count - 1 || filteredSerializedList[index] == null)
                            {
                                filteredItemListDirty = true;
                            }
                            else
                            {
                                filteredSerializedList[index].ApplyModifiedProperties();
                            }
                        }
                    }
                    EditorGUI.indentLevel--;
                }
            }
        }
        public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
        {
            Initialize(property);

            collectableItem = property.objectReferenceValue as CollectableScriptableObject;

            if (optionsAttribute.DrawType == DrawType.AsReference)
            {
                EditorGUI.PropertyField(position, property, label, true);
                return;
            }


            Rect popupRect = position;

            popupRect.height = 15;

            if (collectableItem != null)
            {
                DrawEditFoldoutButton(ref popupRect);
                DrawGotoButton(collection, ref popupRect);
            }

            using (new EditorGUI.PropertyScope(position, label, property))
            {
                popupRect = EditorGUI.PrefixLabel(popupRect, label);

                int indent = EditorGUI.indentLevel;
                EditorGUI.indentLevel = 0;

                bool showMixedValue = EditorGUI.showMixedValue;


                switch (optionsAttribute.DrawType)
                {
                case DrawType.Dropdown:
                {
                    EditorGUI.showMixedValue = property.hasMultipleDifferentValues;

                    DrawDropDown(popupRect, property);

                    break;
                }

                default:
                    throw new ArgumentOutOfRangeException("DrawType: " + optionsAttribute.DrawType);
                }

                if (collectableItem != null)
                {
                    if (CollectionUtility.IsFoldoutOpen(foldoutObject))
                    {
                        EditorGUI.indentLevel++;
                        using (new EditorGUILayout.VerticalScope("Box"))
                        {
                            Editor editor = CollectionUtility.GetEditorForItem(collectableItem);
                            using (EditorGUI.ChangeCheckScope changedCheck = new EditorGUI.ChangeCheckScope())
                            {
                                GUILayout.Space(10);
                                using (new EditorGUILayout.VerticalScope())
                                {
                                    editor.OnInspectorGUI();
                                }

                                EditorGUILayout.Space();

                                if (changedCheck.changed)
                                {
                                    property.serializedObject.ApplyModifiedProperties();
                                }
                            }
                        }
                        EditorGUI.indentLevel--;
                    }
                }

                EditorGUI.showMixedValue = showMixedValue;

                EditorGUI.indentLevel = indent;
            }
        }