Handling NullReferenceException in EditorWindow OnGUI()

I'm working on a custom EditorWindow, but any time I encounter what should throw a NullReferenceException in OnGUI(), the Unity Editor hangs instead.

Example Code:

 // C# example:
 using UnityEngine;
 using UnityEditor;
 using System.Collections.Generic;
 
 public class MyWindow : EditorWindow 
 {
     // Add menu named "My Window" to the Window menu
     [MenuItem ("Window/My Window")]
     static void Init () 
     {
         // Get existing open window or if none, make a new one:
         MyWindow window = (MyWindow)EditorWindow.GetWindow (typeof (MyWindow));
     }
     
     void OnGUI () 
     {
         List<int> mynewList = null;
         Debug.Log(mynewList.Count);
     }
 }

If I open this window via Window->My Window, my unity.exe instantly freezes and must be killed via the Task Manager. Even if I use try...catch blocks in an attempt to catch the exception, it still hangs. Is there a better way of debugging NullReferenceExceptions in EditorWindows without having to restart Unity every time one is hit?

Using Unity3D 3.5.0f5