CustomTransformInspector.cs

using UnityEngine;
using UnityEditor;
using System;


[CanEditMultipleObjects, CustomEditor(typeof(Transform), true)]
public class TransformCustom : Editor
{
    protected bool m_showWorld = false;
    protected Transform m_target;
    protected Editor m_originalEditor;

    private void OnEnable()
    {
        m_showWorld = false;
        m_target = target as Transform;

        Type t = Type.GetType("UnityEditor.TransformInspector,UnityEditor");
        m_originalEditor = Editor.CreateEditor(target, t);
    }

    public override void OnInspectorGUI()
    {
        m_originalEditor.OnInspectorGUI();

        m_showWorld = EditorGUILayout.Foldout(m_showWorld, "World Data");
        if(m_showWorld)
        {
            GUI.enabled = false;

            EditorGUILayout.Vector3Field("Position", m_target.position);
            EditorGUILayout.Vector3Field("Rotation", m_target.rotation.eulerAngles);

            GUI.enabled = true;
        }
    }
}