I was actually aware, in this instance I was running a job with 1/8" mills but I had a ‘fake’ mill with a slightly higher diameter to get it to make a path that left material for a finishing pass. I was merely suprised to see the dialog to change tools even after I stopped the job.
It should be possible to do tool changes on an SO3, so as to accommodate the folks who use depth collars and find their accuracy / precision adequate for a given project. I’ve asked a developer to look into this — hopefully we’ll get an official answer on this later this week.