I've been doing the tube routing tutorial and I'm at the point where I'm supposed to create a flexible tube spline routing. I can create it successfully and it shows me a tube body, but when I exit sketch mode, the solid vanishes and I'm just left with the line. It also happens even if I'm just creating a stub. I've seen people with this same issue going back five or six years and I can't find a concrete answer. Any help would be greatly appreciated.