How to acces to a data list in a custom editor from a editorwindow

Hello,

I customize in the Editor a level editor for my game, i can serialize all my level data parameters in a file.
I'd like to add an EditorWindow which permit drawing elements, and store in a list in my serialize file below.
I don't know how to link my CustomLevel class (my editor data manager) with an EditorWindow.

How to do the link ?

My custom class managed with the inspector launch correctly the EditorWindow:

Code (CSharp):

1.        
2.  
3.    if (GUILayout.Button("Open Grid Window", GUILayout.Width(255)))
4.            {
5.                GridWindowEditor window = (GridWindowEditor)EditorWindow.GetWindow(typeof(GridWindowEditor));
6.                window.BeginWindows();
7.            }

Inside these class i have a lot of serialized loader and writer.

My GridWindowsEditor class is something like this :

Code (CSharp):

1. public class GridWindowEditor : EditorWindow
2. {
3.    public static GridWindowEditor gridWindow;
4.  
5.    ==> ??how to get a reference to my custom class (CustomLevel)
6.  
7.   private static void OpenWindow()
8.    {
9.        GridWindowEditor window = GetWindow<GridWindowEditor>();
10.        window.titleContent = new GUIContent("Grid Window Editor");
11.        gridWindow.Populate();
12.  
13.    }
14.    private void OnEnable()
15.    {
16.    }
17.    private void OnGUI()
18.    {
19.    }
20. }

I'd try a public static CustomLevelEditor refLevelEditor; to reference my target class but i don't know how to instance them.

Do you have an idea ?

Thanks.
Fabb