Citrix Connection Centre analogue on Mac

Hi there,

Our marketing team (mac users) seem to have a hidden Tessitura app which doesn't appear on screen but also "Cant start app" error that you typically get when you try to open the app that's already open. On windows I'd use Connection Centre to shut it down but Mac doesn't have that.  Does anyone know of any alternative?  There is nothing on Citrix forums about it