I have used Archicad for 4 years now and this is a new one. I am using AC 13 at the moment
Apart from the fact that all my library parts are automatically filled with grey ( I read a post here about that), my no 19 pen, the one that was supposed to be white is a light grey. I think that the library problem has something to do with this too.
Though I have changed the settings for my library objects to transparent, I cannot use a white fill for elements that i need in my plan. I want white back!
In the Work Environment settings there is an option called 'Automatic Pen Colour Visibility Adjustment for Model Views' in the On-screen Options area. Untick this and your whites should be white again!