Fix for ArrangeCtrlPositions in commdlg 2

[Mike Hearn]

> By the way, do you think we should implement a look & feel like w2k and
> wxp in addition to the existing one ?

I suppose that depends on whether anybody is feeling motivated enough.
One thing to consider is that we can't use the XP artwork, we'd have to
use probably the KDE or GNOME artwork..... to be honest I'm not sure all
the extra buttons in the new file dialogs are even a good idea. The XP
look and feel includes theming as well, which we don't have support for
either.