Is there a way to prevent the following ?
In setting up a new milling sequence (cutline, profile, etc), with the surface reference collector tab selected and the selection filter set to Mill Volume Surface (MVS) or Mill Surface Surface (MSS), the selection filter goes back to "All" immediately following the selection of the first surface. Then if you want more from the same MV or MS, you have to set it back to MVS or MSS and it then it stays there until you are done selecting surfaces.
Matt