Hi,
If you used the Profile editor for that Detail, you could switch to HTML view and locate the code for removal. It should look something like this:
<font style="BACKGROUND-COLOR: #ffffff"> your text here </font>
The code in red that designates a Font with background with white (color code for white is #ffffff) is what you need to remove. I don't know if you added the background to more than one section. If so, you should see it multiple times.
Danno