While writing this, I'm just asking myself how Roundcube does handle this: As we can't know which skin our users will be using, we need to activate compose_addressbook in the config for the Classic users. Can't this create a conflict with the Larry users, as they would now have a core function AND a plugin with pretty much the same functionality...?
This is not a problem, as my plugin makes sure it only runs with the classic skin.
Cor