Unity:Auto-hid launcher leaves invisible area

[Toshi Esumi]

I have Ubuntu 12.10 with Unity 6.12.0 running. I recently noticed that
auto-hide of launcher still works but when it's hid it leaves a blank
area where I can't see anything when I move one of app windows to the
area. Is anyone else experiencing this symptom? I think this started a
couple of days ago. I run software update almost every night and I'm not
sure if one of them caused this or not.

Toshi