[h-e-w] artifacts left on screen when faces have background color?

[Scott Jaderholm]

Hi Emacs Users,

I've found that using a face with a background color set will
occasionally leave thin vertical bars on the screen after the face is
no longer in use. I first saw this with highlight-tail.el, but as you
can see in http://jaderholm.com/temp/emacs-artifact1.gif it happens
with built-in functionality as well.

In isearch I get it as well after I look at a result. My inactive face
is darker than the active search results face and you can see in
http://jaderholm.com/temp/emacs-artifact2.gif that it's left a thin
vertical bar next to some of the inactive search results that I've
already cycled past.

If anyone has an idea why it's doing this or how to fix it I would
appreciate the help.

Thanks,
Scott