Glitch Problem in Adobe Flash CS6 - Help?

I've continuously encountered this glitch while animating in Adobe Flash CS6 where it will turn symbols invisible without warning. I never clicked the invisible command, but it will make the symbol completely disappear. It usually happens right after I make an edit inside of a symbol, then exit out to view it along with the others. It still responds if I click it or move it around, but it will still remain unseeable. The only way to fix it is to save the Flash file and reopen it. It's not much a problem, but it's honestly aggravating because it happens much more frequently. Anyone having the same issue?