Good questions, I just opened another project and its doing the same problem.
All objetcs, zones, walls that have been specified to have white as the back ground show as grey.
Ive attached a pic to illustrate what I mean.
I changed the settings in both the tools settings and the pens and colours dialog.
Just opened a new project using standard setting and template and I dont have the problem.
UPDATE Ok, when I open the project with standard Arch14 template and settings, the problem isnt there anymore, but I dont have my customised pen sets of course,