I don't even know where to begin.
I have a db...In every layout for every table—in spite of the fact that their parts all have a white fill—the background turns red in preview mode. I'm using 12, so if I change the theme, this doesn't happen, but if I change the theme back to classic, I get the red background again. I put white rectangles covering the layout parts and that helps; except at the part boundaries, you can still see red and there's nothing you can do about it.
Any ideas where to being troubleshooting? I found out that if I remove the white background fill, the default color is red...in classic...So what that seems to mean, then, is that in preview mode, my white background is being stripped away. The clumsy solution was to select a new theme, turn everything white, remove the alternating body fill, and copy the layout objects onto this new layout. But I want this red background thing to make sense to me!
So thanks for any ideas at all.