I would like to customize the default Category editor, to assist the editors in selecting the right categories.

For example, for a ProductPageType, I would like to limit the Category editor to show only categories relevant to a product page.

I have not had any luck accessing/modifying the available categories for the dialog in an EditorDescriptor for the "CategoryList" type.

Notice, I am not trying to add a custom property, but rather manipulate the builtin "PageData.Category" of all pagetypes.