Newbie here. So I have no idea why Fusion 360 is doing what it's doing, but here's what's going on. I'm in the middle of designing something, and I get to a point where I need to do another sketch on a surface of an existing object which has been extruded. I enter sketch mode, click on the surface of the object that I want to sketch on, and what happens is certain objects move back to their original locations; where they were a while ago when I initially drew them. I've since moved them. I kind of need them to be there while sketching because I'm using them as reference points. And the only way to bring them back is to exit sketch mode. After initially moving the objects, I did click on the "Snapshot" button at the top. While the objects are invisible, I do notice, looking at the timeline below, that the last 13 actions are greyed out for whatever reason. The "playhead" is at the very end, past the last greyed out action. I've never had this happen before, why is it doing this? I even tried deleting the objects that kept moving, then recreating them in the spot that I want, but now when I enter sketch mode, the 2 objects in question simply disappear. That's because their creation was among the last 13 actions I performed, and they were greyed out along with others. The only time this occurs is when I try to sketch on a specific surface. It doesn't do it when I sketch on any other surface.
The item I'm designing is at http://a360.co/1QS0MtJ
The surface I'm trying to sketch on is the underside of the table top.
