Problem with switch layer disappearing

[madrobot]

I have a folder with 3 different switch layters in it (my mouth rig) which disappears sometimes (cannot be made visible, still in layers window but not in main window, doesn't render.
Sometimes it disappears and you can (in an action for example) get it to reappear by selecting a child switch layer inside the folder. (Undo seemed on this occasion to render the layer invisible.)

There doesn't seem to be much ryhme or reason to it, has anyone else come across this issue? (Appears to be a bug.)

I could try re-importing the mouth. But I should not have to.

[Víctor Paredes]

Weird. Can you post the file?

[madrobot]

Aaaaaaannnnnnd it turns out that I set opacity to ZERO.
Disregard. Don't hangup. Sorry for wasting everyone's time. I'm OK. Thanks for asking.
Thankyou to Chuck for discovering my embarassing error. Whoooooooeeee.

[neeters_guy]

It's good lesson nonetheless. Thanks for posting a followup.