Impossible to make the Visual Studio PropertyGrid use my custom FileNameEditor derived class

[cadilhac]

• .NET Core Version:
  .Net 6

• Have you experienced this same bug with .NET Framework?:
  No, it works perfectly with the .Net Framework

Problem description:
I want to use a custom FileNameEditor for a custom control property. I derived from FileNameEditor like so:

public class MyFileNameEditor : System.Windows.Forms.Design.FileNameEditor
{
    protected override void InitializeDialog(OpenFileDialog openFileDialog)
    {
        base.InitializeDialog(openFileDialog);

        openFileDialog.Filter = "My files (*.custom)|*.custom";
    }
}

I applied it like so:

[Editor(typeof(MyFileNameEditor ), typeof(System.Drawing.Design.UITypeEditor))]
public string MyFileName
{
    set [...]
    get [...]
}

In the VS designer, when selecting the custom control, inside the PropertyGrid, the property will have no editor.
Note that if I use the stock FileNameEditor instead, it just works.