I just had a fun time putting a pocket on a 3D contour, it was a 2D pocket but you need a 2D sketch to make a 2D pocket fast, and I have no idea how to project lines into a 2D sketch rapidly so I dicked around with solid edges and two paths for 1/2 an hour to get it, and then I copied a 2D contour and somehow paste deleted the operation above it.

No undo. Sweet. Awesome. Screw me then. Undo is so basic. It's crazy. Why wouldn't that be possible?