Previously multiple selection of sketch entities for extruding or removing any area was a big hassle and it was leading to great loss of time and confusion.
Sometime wrong selection creates uneven extrudes and leads to failure in improper part development.Now in just a single press to an ALT key, you can select multiple sketch entities and get a ride from uneven selection.
SOLIDWORKS 2017 has a capability that the context menu that appears after selecting the two contours can be customized to add the Cut-Extrude command to it. To customize it RMB on it when it’s displayed. The same applies to the context menu that appears when clicking on a shaded contour region.