The details panel is supposed to save its position, but I have heard that it's an issue in some cases (I've been hearing that for a long time and just haven't addressed it yet). In my simple testing, it seems to work, but something must be resetting it or something strange. Oh wait...I just figured it out lol. So if you close it out and restart, it's not saved. Hey, I get it! I'll add that to my short list.