[Gtk-sharp-list] Gtk.DrawingArea + ModifyFG causes crash

[White Spirit]

Adding the following event handler to a Gtk.DrawingArea causes mono to 
exit inexplicably:

private static void ConfigureEvent (object obj, ConfigureEventArgs args)
   {
   Gdk.EventConfigure ev = args.Event;
   window = ev.Window;
   Gdk.Rectangle allocation = d.Allocation;

   pixMap = new Gdk.Pixmap (window, allocation.Width, allocation.Height);
   d.ModifyFg (StateType.Normal, new Gdk.Color (255,255,255));
   pixMap.DrawPoint(d.Style.ForegroundGC(StateType.Normal), 50, 50);
   args.RetVal = true;
   }

What is the proper way to assign a foreground colour when using double 
buffering?