Creating editor for serializable class

Unity Engine
1

Im not even sure it is possible but Id like to display a custom editor for a class in my behaviour. My setup is like this:

[System.Serializable]
public class Test
{
public bool A;
public int B;
}

public class TestBehaviour : MonoBehaviour 
{
[SerializeField]
    protected Test[] array= new Test[8];
}

// window is used to inspect specific Test objects
public class TestWindow : EditorWindow
{
    Test T;
        
    public void Set(  Test T )
    {
        this.T = T;
        Repaint();
    }
    
    void OnGUI()
    {
        if( T != null )
        {   
            var editor = Editor.CreateEditor(T); // obviously can't work because T is not a UnityGame.Object
            editor.OnInspectorGUI();
        }        
    }
}

If anyone has recommendation for me, please let me know. Most probably there is better way to setup.

2

Why would you want to create an Editor while OnGUI?

Editor are displaying automatically on the Inspector when your object is selected.

3

You’re right, when I select the behaviour it displays the Test class array data fine. I can open the array and edit the items.

However when the array is large, its a bit tedious to scroll thru all of them so I wanted to create an editor window to edit individual Test items. I have a method to select individual array element by clicking on them in the viewport.