UnitySerializedReferenceUI/Editor/Attributes/SerializeReferenceMenuAttributeDrawer.cs

#if UNITY_EDITOR
using System;
using System.Collections.Generic;
using UnityEditor;
using UnityEngine;

namespace Textus.SerializeReferenceUI.Editor
{
    [CustomPropertyDrawer(typeof(SerializeReferenceMenuAttribute))]
    public class SerializeReferenceMenuAttributeDrawer : PropertyDrawer
    {
        public override float GetPropertyHeight(SerializedProperty property, GUIContent label)
        {
            return EditorGUI.GetPropertyHeight(property, true);
        }

        public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
        {
            EditorGUI.BeginProperty(position, label, property);

            IEnumerable<Func<Type, bool>> typeRestrictions = SerializedReferenceUIDefaultTypeRestrictions.GetAllBuiltInTypeRestrictions(fieldInfo);
            property.ShowContextMenuForManagedReferenceOnMouseMiddleButton(position, typeRestrictions);

            EditorGUI.PropertyField(position, property, true);
            EditorGUI.EndProperty();
        }
    } 
}
#endif