Roundcube Trash Folder Fill Up

Anyone figured out the best way to get Roundcube to empty the trash folder when mail is deleted from external clients? I know there is Roundcube conf but editing many conf files is not the best approach with web control panels. Often systems like IW will overwrite manual changes. So this brings me to the forum.

Users are deleting mail using IMAP clients but in Roundcube that mail is just piling up in the Roundcube trash folder. I know Roundcube has the function to delete on logout but many accounts aren't accessed via Roundcube but with external clients like Pegasus, Pop Peeper, Thunderbird, etc.

Thanks!