Storing accessible roles in class private is problematic
We end up having the usual problem whenever we store things in class privates: They are not available when we accidentally want to use them in init().
Case in point: GtkLinkButton derives from GtkButton, and GtkButton sets its accessible role to 'button' in class_init, but link buttons end up with an accessible role of 'widget' anyway.
The same happens for GtkDialog subclasses.
Edited by Matthias Clasen