How to Undo a bool on an EditorWindow

I have been tackling this issue for a while but I cant get any results. I get the “Happened” messaged on the console, and if I go to the Edit>Undo, i see “testing” after it, meaning it recorded the change.

But when I press it, or do Ctrl-Z nothing happens. The bool testing has to be public and static because I also want to change her throght a MenuItem.

I have tried multiple approaches this was one of them

    using UnityEngine;
    using System.Collections;
    using UnityEditor;
    public class MapMaker2D : EditorWindow {

    	//instance of this script
    	public static MapMaker2D instance;
    	public static bool testing;
    	//runs whenever the window is created
    	void OnEnable()
    		//sets instance of mapmaker
    		instance = this;
    void OnGUI()
                   EditorGUI.BeginChangeCheck ();
    		bool atesting=EditorGUILayout.Toggle (new GUIContent("testing","testing variable"),testing);
    		if (EditorGUI.EndChangeCheck ()) {
    			Debug.Log ("Happened");
    			Undo.RegisterCompleteObjectUndo(this, "testing");

turns out you have to make testing non-static, and update it according to a static bool whenever you want to change it via menu item