I've been adding window/panel docking to &half-edge, and I had to figure out the problem of "which side would you expect a panel to dock, given every potential drop point in the target panel?", which was way harder to get right than I thought!

I started out with a simple "distance from edge" solution, and then I tried a "normalized distance from edge", and then a few more others, but they had problems of feeling either too sticky or too unresponsive. I thought about it some more and now I have a continuous variant that handles both borders and some heuristics in the middle for what people likely expect c: gonna try it out now!