gtk:menu-button-set-create-popup-func (button func)

button -- a gtk:menu-button widget
func -- a gtk:menu-button-create-popup-func callback function to call when a popup is about to be shown, but none has been provided by other means, or nil to reset to default behavior

Sets func to be called when a popup is about to be shown. The callback function should use one of the gtk:menu-button-popover or gtk:menu-button-menu-model functions to set a popup for the menu button. If func is non-nil, the menu button will always be sensitive.

Using this function will not reset the menu widget attached to the menu button. Instead, this can be done manually in the callback function.