On one of my parts in an assembly one of the underlying sketches is showing up on the part surface a drawing view.  It isn't showing up in any of the assemblies it is used in, but only in the drawing view.  I know I can go in and hide it in the drawing view, but I don't know why it is showing to begin with?  I opened the part and showed the sketch, and then hid the sketch and it went away in the drawing view, but then a few minutes later it was back?

Any ideas?