I am having a weird issue with my layers. I draw a bunch of polygons and at some point when panning the map or something else that requires a redraw, I lose some or all pf the polygons from the map. Sometimes this is a redraw issue and redrawing again resolves it. However, other times the polygons disappear. Closing and opening the program doesn't bring them back. They are gone. It seems any layers that were checked when it occurs are affected. Anyone have any ideas? I've just lost 2 or 3 hours worth of work.