I understand what you are asking, @etfrench. You want sketch extend to be a two-selection operation. The curve to extend, and the target. This was just a design choice. For 80% of the extend cases, the current extend is better, because the "extend to" curve is obvious. It's just a single click, instead of two. Where it gets tedious is if you have a lot of virtual intersections, as in your case. This is where we extend to the infinite extension of another curve in the sketch. You might ask why we need to support virtual intersections. The main reason is this kind of case:
You want to extend both lines to meet. If we don't support virtual intersections, this cannot be done.
So, that's the reason. I agree in your case it is tedious. I would probably just draw another line and make it colinear in those cases.
Jeff
Jeff Strater
Engineering Director