clickableObjectEditor.cs

using UnityEngine;
using UnityEngine;
using UnityEditor;
using UnityEditorInternal;

[CustomEditor(typeof(ClickableObject))]
public class ClickableObjectEditor : Editor {
    private ReorderableList list;

    private void OnEnable()
    {
        list = new ReorderableList(serializedObject,serializedObject.FindProperty("Required"),true, true, true, true);

        //Draw the rect for the list
        list.drawElementCallback =
        (Rect rect, int index, bool isActive, bool isFocused) => {
            var element = list.serializedProperty.GetArrayElementAtIndex(index);
            rect.y += 2;

            EditorGUI.PropertyField(
                new Rect(rect.x, rect.y, 150, EditorGUIUtility.singleLineHeight),
                element.FindPropertyRelative("Type"), GUIContent.none);


            EditorGUI.PropertyField(
                new Rect(rect.x + 150, rect.y, 100, EditorGUIUtility.singleLineHeight),
                element.FindPropertyRelative("id"), GUIContent.none);

            if (element.FindPropertyRelative("Type").enumValueIndex == 2)//Only show this if it is relevant
            {

                EditorGUI.TextArea(
                new Rect(rect.x + 300, rect.y, 100, EditorGUIUtility.singleLineHeight),
                "Destroy Item");

                EditorGUI.PropertyField(
                    new Rect(rect.x + 400, rect.y, 100, EditorGUIUtility.singleLineHeight),
                    element.FindPropertyRelative("RemoveItem"), GUIContent.none);

            }
        };
        list.drawHeaderCallback = (Rect rect) => {
            EditorGUI.LabelField(rect, "Requirements");
        };
    }

    public override void OnInspectorGUI()
    {
        serializedObject.Update();

        //SuccessActions
        SerializedProperty _SuccessActions = serializedObject.FindProperty("SuccessActions");
        EditorGUI.BeginChangeCheck();
        EditorGUILayout.PropertyField(_SuccessActions, true);
        if (EditorGUI.EndChangeCheck())
            serializedObject.ApplyModifiedProperties();

        //FailActions
        SerializedProperty _FailActions = serializedObject.FindProperty("FailActions");
        EditorGUI.BeginChangeCheck();
        EditorGUILayout.PropertyField(_FailActions, true);
        if (EditorGUI.EndChangeCheck())
            serializedObject.ApplyModifiedProperties();


        list.DoLayoutList();
        serializedObject.ApplyModifiedProperties();
    }
}