问为什么BeginScrollView在检查器编辑器脚本中可以正常工作，但在编辑器窗口脚本中不能工作？

EN

using System.Collections;
using System.Collections.Generic;
using UnityEditor;
using UnityEditorInternal;
using UnityEngine;

[CustomEditor(typeof(ConversationTrigger))]
public class ConversationTriggerEditor : Editor
{
    private Vector2 scrollPos;
    private ConversationTrigger conversationtrigger;

    private void OnEnable()
    {
        conversationtrigger = (ConversationTrigger)target;
    }

    public override void OnInspectorGUI()
    {
        scrollPos = EditorGUILayout.BeginScrollView(scrollPos, GUILayout.Height(250));
        DrawDefaultInspector();
        EditorGUILayout.EndScrollView();

        if (GUILayout.Button("Add new conversation"))
        {
            conversationtrigger.conversations.Add(new Conversation());
        }

        GUILayout.Space(10);
        if (conversationtrigger.conversations.Count == 0)
        {
            GUI.enabled = false;
        }
        else
        {
            GUI.enabled = true;
        }
        if (GUILayout.Button("Remove conversation"))
        {
            if (conversationtrigger.conversations.Count > 0)
                conversationtrigger.conversations.RemoveAt(conversationtrigger.conversations.Count - 1);
        }

        GUILayout.Space(100);
        if (GUILayout.Button("Save Conversations"))
        {
            conversationtrigger.SaveConversations();
        }

        GUILayout.Space(10);
        if (GUILayout.Button("Load Conversations"))
        {
            Undo.RecordObject(conversationtrigger, "Loaded conversations from JSON");
            conversationtrigger.LoadConversations();
        }
    }
}

using System.Collections;
using System.Collections.Generic;
using UnityEditor;
using UnityEditorInternal;
using UnityEngine;

public class ConversationsEditorWindow : EditorWindow
{
    Vector2 scrollPos;

    [MenuItem("Conversations/Conversations System")]
    static void Init()
    {
        const int width = 800;
        const int height = 800;

        var x = (Screen.currentResolution.width - width) / 2;
        var y = (Screen.currentResolution.height - height) / 2;

        GetWindow<ConversationsEditorWindow>().position = new Rect(x, y, width, height);
    }

    void OnGUI()
    {
        var ff = FindObjectOfType<ConversationTrigger>();
        EditorGUILayout.BeginVertical();
        EditorGUILayout.BeginScrollView(scrollPos, GUILayout.Width(800), GUILayout.Height(800));
        var editor = Editor.CreateEditor(ff);
        var tar = editor.targets;
        editor.OnInspectorGUI();
        EditorGUILayout.EndScrollView();
        EditorGUILayout.EndVertical();
        Repaint();
    }
}