This is probably a minor, but in the preferences you can apparently set the viewer background color in two places (as it seems) but only one is working.
In Listers -> Viewer Pane tab
and
Viewer -> Viewer tab
the Listers -> Viewer Pane tab is the one that seems to be working since nothing seems to happen when I change the other one.
(I might be missing something here?!)
/Pontus