title: How can I use ReorderableList with a List in the Inspector and adding new empty items and collapse childs?
body: <p>This is how I declared the List :</p>
  
  <pre><code>using System;
  using System.Collections;
  using System.Collections.Generic;
  using System.IO;
  using System.Linq;
  using UnityEditor;
  using UnityEngine;
  using UnityEditorInternal;
  
  public class ConversationTrigger : MonoBehaviour
  {
      public List&lt;Conversation&gt; conversations = new List&lt;Conversation&gt;();
  </code></pre>
  
  <p>This is the editor script using this List :</p>
  
  <pre><code>using System.Collections;
  using System.Collections.Generic;
  using UnityEditor;
  using UnityEditorInternal;
  using UnityEngine;
  
  [CustomEditor(typeof(ConversationTrigger))]
  public class ConversationTriggerEditor : Editor
  {
      private ReorderableList ConversationsList;
  
      private void OnEnable()
      {
          ConversationTrigger conversationtrigger = (ConversationTrigger)target;
          ConversationsList = new ReorderableList(serializedObject, serializedObject.FindProperty("conversations"), true, true, true, true); 
      }
  
      public override void OnInspectorGUI()
      {
          serializedObject.Update();
          ConversationsList.DoLayoutList();
          serializedObject.ApplyModifiedProperties();
          EditorUtility.SetDirty(target);
      }
  }
  </code></pre>
  
  <p>This is a screenshot of the Inspector before using the ReorderableList. I could click on a Conversation item and collapse it and then on each child to collapse it again and so on :</p>
  
  <p><a href="https://i.stack.imgur.com/8BH0h.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/8BH0h.jpg" alt="Before using ReorderableList"></a></p>
  
  <p>And this screenshot is when using the ReorderableList :</p>
  
  <p><a href="https://i.stack.imgur.com/yoVMn.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/yoVMn.jpg" alt="When using ReorderableList"></a></p>
  
  <p>Now I can only drag the items and change places and when clicking on + it will add a duplication of the last item.</p>
  
  <p>What I want to do for now I can think of at least 3 things :</p>
  
  <ol>
  <li><p>When selecting existing item for example Opening and then if clicking on the + add a new empty Conversation item under the Opening. If I selected the Magic add empty new one to the end and if selected the one in the middle Locked Room add empty item after it. The idea is to add empty item after the selected item.</p></li>
  <li><p>When removing item/s same the selected one/s</p></li>
  <li><p>How can I make that when clicking double click on one of the items or making a arrow that will collapse the items and show all the childs like in my screenshot in my question like Opening and others ?</p></li>
  </ol>