[Orgmode] date rows in weekly agenda column mode

[George Pearson]

In column view for the weekly agenda, the rows containing the dates for
the upcoming week (e.g. "Friday  17 October 2008") have the same light
grey background as the rows containing the TODO items.  Is there a way
to set a different background (like, say, white) for these date rows?
This would make the date separations more obvious in this display.

I have been poking around in org-faces.el but could not figure out
if anything controlled this background in particular.