Problem with locked layer...

I'm attempting to finish some artwork, and I seem to have run into a problem. I duplicated a layer--filled with white--and locked the transparent pixels in the duplicated layer. When I try to color over it, there are some white pixels showing about the edges. Inexplicably, these white pixels don't even seem to be in the layer that I'm trying to color at all--but the original layer underneath. When I hide the original layer, the white pixels disappear. What's going on?

Here's a screencap:
http://img.photobucket.com/albums/v388/Veeva/WTH.jpg

I'm not sure I follow your methodology, or what you are trying to accomplish. Why are you keeping a white layer visible underneath that you are painting over? Are you keeping it around so you can ctrl-click to reselect the shape? How are you 'coloring' over it? It sounds like you are having some anti-aliasing in the duplicated layer that is affecting your ability to color all pixels that you want?

Try this... don't duplicate the layer and 'lock' transparent pixels. Instead, create an empty layer above your white layer that defines your 'shape'. With the empty layer active, ctrl-click (or Mac equiv) on the white layer icon below it (in the layers pallete) to get your marching ants, then paint in the empty layer as you will...

I bet (again) it's some aliasing issue with the lockage.