just a note that dovecot sieve also support vacation with leads to the 3rd plugin managesieve for vacation support
Making vacation setting in a separate tab will be better. We have many customers ask "How can i setup vacation message" with Roundcube and managesieve plugin.
We have adapted one of the vacation plugins to use managesieve and have it's own simple "Vacation" tab under preferences, and have been meaning to try and get our changes added to that plugin. . . Plus now there is the new skin, which sounds like requires changes to plugins. . .
Who wants to help here?
Benjamin