Part disappeared

Greetings,

I was adding holes to a set of existing holes in a chassis and after the holes were created, the whole part became invisible.  I can't figure out what happened.  When I run the mouse cursor in the design tree, the various sketches highlight on the screen.  I've been working on this part for weeks and nothing like this has ever happened- never seen this behavior before at all.

Thanks for any suggestions.

Roger

SolidworksSheet Metal