Adding panels to NLA Editor

Hi, I have one question about Blender UI’s. I added a panel to the material tab, but no I need to add a panel here: (The right panel)

I haven’t found any bl_context to add it there, so that’s why I ask. Thanks!

    bl_space_type = 'NLA_EDITOR'
    bl_region_type = 'UI'

Thanks, it worked, but I can’t add a property, it gives an “ expected a AnyType type, not tuple”. But I can’t see any difference with a working material panel, so…
What can I do?

It seems that you try to create a custom property on a non-ID type

How do I add custom property to certain kinds of datablocks?