Question Object picker broken for third column on horizontal layout

Hello,

I'm trying layout list editor horizontally like this:


However, object picker is not working for third or later columns:


How can I solve the problem? Any comment will be appreciated.

<notes>

1. Wider or thinner width didn't solve
2. Problem appears if third or later column is Array or List of object
3. If this problem couldn't be solved, I might want to make tools csv -> ScriptableObject converter

<code>

Code (CSharp):

1. using UnityEngine;
2. using UnityEditor;
3.  
4. public class Example : EditorWindow
5. {
6.     // settings
7.     [SerializeField] AnimationClip[] _a;
8.     [SerializeField] GameObject[] _b;
9.     [SerializeField] AnimationClip[] _c;
10.     [SerializeField] AudioClip[] _d;
11.     float _width = 180f;
12.     float _height = 20f;
13.  
14.     [MenuItem("Example/Example")]
15.     static void Init()
16.     {
17.         var window = GetWindow<Example>("Window");
18.     }
19.  
20.     private void OnGUI()
21.     {
22.         var so = new SerializedObject(this);
23.         so.Update();
24.         // layout horizontally
25.         EditorGUILayout.BeginHorizontal(GUI.skin.box);
26.         EditorGUILayout.PropertyField(so.FindProperty("_a"), true,
27.             GUILayout.Width(_width), GUILayout.Height(_height));
28.         EditorGUILayout.PropertyField(so.FindProperty("_b"), true,
29.             GUILayout.Width(_width), GUILayout.Height(_height));
30.         EditorGUILayout.PropertyField(so.FindProperty("_c"), true,
31.             GUILayout.Width(_width), GUILayout.Height(_height));
32.         EditorGUILayout.PropertyField(so.FindProperty("_d"), true,
33.             GUILayout.Width(_width), GUILayout.Height(_height));
34.         EditorGUILayout.EndHorizontal();
35.         so.ApplyModifiedProperties();
36.     }
37. }
38.