ネストクラス（ScriptableObject）

FindLight.cs

using UnityEngine;
using System.Collections;
using UnityEditor;
using System.Linq;

[CreateAssetMenu( menuName = "ScriptableObject/EditorAction", fileName="EditorAction")]
public class FindLight : ScriptableObject 
{
	[SerializeField] LightType lighttype = LightType.Directional;

	private void Find()
	{
		var lights = GameObject
			.FindObjectsOfType<Light> ()
			.Where (c => c.type == lighttype)
			.Select (c => c.gameObject)
			.ToArray ();
		Selection.objects = lights;
	}

	[CustomEditor(typeof(FindLight))]
	class FindLightEditor : Editor
	{
		public override void OnInspectorGUI ()
		{
			base.OnInspectorGUI ();

			if( GUILayout.Button("Action")){
				Instance.Find();
			}
		}

		FindLight Instance
		{
			get{ return (FindLight)target; }
		}
	}
}