Got a backup :) Actually I backed up the entire UI directory just in case. The background change for P5 doesn't seem to work in P6 NukedBug. Works for a brief moment during startup (the background went black for about 3 seconds). But you end up with the default grey eventually. Am going to try a visual xml editor to see if I can figure it out a bit better.

Only your mind limits yourImagination. Let it free.