Custom Editor for GameObject Class look like Unity's Custom Inspector for GameObject?

Hi, I’m trying to make a Unity Custom Editor for the GameObject Class. I’d like it to look just like the Untiy Custom inspector pictured below with an extra button showing beneath it.

alt text

So I thought I’d call DrawDefaultInspector because that will draw what it looks like by default using the following code:

using UnityEngine;
using UnityEditor;

[CustomEditor(typeof(GameObject))]
public class InspectorNewScriptButton : Editor 
{

    public override void OnInspectorGUI() 
	{
        DrawDefaultInspector();
        if(GUILayout.Button("Press Me")
            Debug.Log("Pressed");
	}
}

Instead however… I ended up with this mess:

Default Inspector

How would I go about making my custom script look/work like Unity’s Custom Default not the real default and then add an additional button to it? Is there a call to Unity’s Custom Inspector that I’m not aware of?