Found a bunch of unanswered threads, unsure which best to reply my workaround to, I figured a new thread puts the latest date on the google results, so here we are.
My case I have a very complex multi body part and sometimes if I go to edit a feature then when the edit state is entered the geometry disappears, even though the body is not "hidden". So I'm blind and can't solve the problem.
Figured out the workaround just now, which is open the double pane on the left so you can see the edit feature in one and the feature tree same time. Then while in edit feature and the unhidden body is invisible, in the feature tree in the solid bodies folder, right click the body and select hide then unhide, and it's visible again!!!!!!