OnValidate Creates Unwanted Duplicate Custom EditorWindows

2019.3.11f1

Hey so I've got a custom editor window that implements OnValidate and attempts to refresh itself at runtime and in editor. Here are two examples of it breaking:

Code (CSharp):

1. using UnityEngine;
2. using UnityEditor;
3.  
4. [InitializeOnLoad]
5. public class CustomEditorWindow : EditorWindow
6. {
7.    
8.     public static CustomEditorWindow GetCustomEditorWindow()
9.     {
10.         return GetWindow<CustomEditorWindow>();
11.     }
12.  
13.     private static CustomEditorWindow m_Window;
14.     public static CustomEditorWindow s_Window
15.     {
16.         get
17.         {
18.             if (m_Window == null)
19.             {
20.                 m_Window = GetCustomEditorWindow();
21.             }
22.  
23.             return m_Window;
24.         }
25.     }
26.    
27.     [MenuItem("Window/Custom Window", false, 200)]
28.     private static void OpenCustomWindow()
29.     {
30.         Debug.Log(s_Window);
31.     }
32.  
33.     private void OnValidate()
34.     {
35.         OpenCustomWindow();
36.     }
37. }
38.  

The above yields duplicate CustomEditorWindows on OnValidate.

Code (CSharp):

1. using UnityEngine;
2. using UnityEditor;
3.  
4. [InitializeOnLoad]
5. public class CustomEditorWindow : EditorWindow
6. {
7.    
8.     public static CustomEditorWindow GetCustomEditorWindow()
9.     {
10.         while (((CustomEditorWindow[])Resources.FindObjectsOfTypeAll(typeof(CustomEditorWindow))).Length > 0)
11.         {
12.             ((CustomEditorWindow[])Resources.FindObjectsOfTypeAll(typeof(CustomEditorWindow)))[0].Close();
13.         }
14.        
15.         return CreateInstance<CustomEditorWindow>();
16.     }
17.  
18.     private static CustomEditorWindow m_Window;
19.     public static CustomEditorWindow s_Window
20.     {
21.         get
22.         {
23.             if (m_Window == null)
24.             {
25.                 m_Window = GetCustomEditorWindow();
26.             }
27.  
28.             return m_Window;
29.         }
30.     }
31.    
32.     [MenuItem("Window/Custom Window", false, 200)]
33.     private static void OpenCustomWindow()
34.     {
35.         Debug.Log(s_Window);
36.     }
37.  
38.     private void OnValidate()
39.     {
40.         OpenCustomWindow();
41.     }
42. }

In this case, we'll see a nullref when it gets to the Close function in GetCustomEditorWindow.

What's interesting is that in printing out the value of the [0] element in FindObjectsOfTypeAll we have found that it is not null.

Relaunching Unity editor with one of these windows open will also spawn an additional window that exists outside of the original Unity window (ie separate window in the Windows taskbar/dock.) See below:



Closing the external EditorWindow gives the other one a Failed to Load title.

Also, the only thing that truly clears 'ghost' windows (when it's saying there's a window open and there clearly is not) is resetting the Layout of the Unity editor at large.

 

Here's the screenshot as it looks like the Imgur post failed to link properly.

 

Code (CSharp):

1. using UnityEngine;
2. using UnityEditor;
3.  
4. [InitializeOnLoad]
5. public class CustomEditorWindow : EditorWindow
6. {
7.     private static CustomEditorWindow m_Window;
8.     public static CustomEditorWindow s_Window
9.     {
10.         get
11.         {
12.             m_Window = (CustomEditorWindow)CustomEditorWindow.GetWindow(typeof(CustomEditorWindow));//GetCustomEditorWindow();
13.        
14.             return m_Window;
15.         }
16.     }
17.  
18.     [MenuItem("Window/Custom Window", false, 200)]
19.     private static void OpenCustomWindow()
20.     {
21.         Debug.Log(s_Window);
22.         s_Window.Show();
23.     }
24.  
25.     private void OnValidate()
26.     {
27.         OpenCustomWindow();
28.     }
29. }