Face color change in column view

[Wanrong Lin <wanrong.lin@gmail.com>]

I wonder whether anyone sees the same thing as I did:

I use a light background. When column view is turned on, I got some 
silver background, but my level 2 headings changed their foreground 
color from default (black) to my light background color. So I have light 
color texts on top of silver background, which makes them really 
difficult to read. The strange thing is, if I set my org-level-2 face to 
the following (using custom-set-faces):

'(org-level-2  ((t (:foreground "#000000"))))

I don't have the problem. But if I set org-level-2 to the following:
 
'(org-level-2 ((t nil)))   ;; just use default face

I got the problem. Both of the settings are black since my default 
foreground is black for light background. So why is that?

I want to avoid hard coding org-level-2 to black because occasionally I 
need to work in a SSH terminal window with black background.

Thanks if someone can give some hints/ideas.