I'm trying to implement a new "archive"-attribute (similiar to "create" and "delete"), with which I'm trying to control whether the Archive-function shows in the action dropdown menu.

Everything works great and I can define whether or not to show the action on a view per view basis. However, while there's apparently no schema validation for Form views, there's one for basically every other view.

So when I write:

tree archive="0"

 it still works, but I get an error every time I try to update the corresponding module because the view validation fails.

The validation is handled in view_validation.py and I'd prefer to not mess with it, so I was looking into expanding the schema which is defined in base/rng/tree_view.rng and directly called in view_validation.py/relaxng.

Is there an easy way of adding an additional attribute to the schema or do I just have to resort to using CSS classes instead?