What does bDisplayInSubMenuHeader control?

Does anyone know what column bDisplayInSubMenuHeader in table sys_objects_actions controls?

This table contains what appear to be Action Block buttons, and based on its name, I would imagine this boolean column would control display of action buttons in the submenu header area (see attached image), but I've toggled values between 0 and 1 and it doesn't seem to have any effect, at least not in the submenu header area.

Thanks

DId you clean cache?

Yes, several times. Let me know if there's anything else I should be doing.