Hummm, this seems to be working on the MSTW Dev site …
Did you SAVE the changes? (Save button is at the bottom of the (long) page.)
You mention “the found and background color”, but there are several … for headings, for the title, for even rows, for odd rows … did you set the right one(s)??
Did you create any custom CSV rules related to these settings? They can override the ‘defaults’ from the Settings screen.
Also, it would be helpful if you send me a link to the page in question.
-Mark