commit -- Tweak Win32 background color option

[Tom Briggs]

Fixed Win32 prefs dialog to not save the background color if the
Allow background color checkbox is turned off
CVS: ----------------------------------------------------------------------
CVS: Enter Log.  Lines beginning with `CVS:' are removed automatically
CVS:
CVS: Committing in .
CVS:
CVS: Modified Files:
CVS:    src/wp/ap/win/ap_Win32Dialog_Options.cpp
CVS: ----------------------------------------------------------------------