Paths going invisible in Illustrator?
I'm working with objects with multiple paths in Illustrator. I selected all my paths in one object, moved them slightly, and most of the paths went invisible. They still exist: I can select them, but not see them except for the selected outlines.
Command Z reverts the last step, but does not reverse the invizibility
I reverted to my most recent saved version, tried manipulating those paths - no problem. Then I transform>reflected the whole object, and whoosh, most of the paths are gone again.
Reverted and tried again, could manipulate for a while, and then was changing one path's shape, and it disappeared.
Any idea what's going on, how I fix it and get my visible paths back, and avoid causing this problem in the future? 
