[Usability] notebook-less dialogs

[Robert Staudinger <robsta stereolyzer net>]

Hello, 

Figure 3.24. "An example of a dialog" of the GNOME HIG 2.0 (Chapter 3.
Windows -> Dialogs) suggests that a notebook widget should be used in a
dialog even if it only has only one page. Am I interpreting that
correctly?
If no notebooks are required, would you suggest to insert a horizontal
line right above the standard buttons?

Thanks, 
Rob