User interface programming XUL?

I have seen a little bit on Application user interface standards and tools
for creating user interfaces within applications.

Is there some sites where there is more details on application user
interfaces, todate I have seen only
XUL Tutorial
http://www.xulplanet.com/tutorials/xultu/
XPToolkit Architecture
http://www.mozilla.org/xpfe/aom/AOM.html

The GNUe Form Definition Language
http://gnue.org/docs/GNUeFormsTechRef/x303.html

Scalar vector graphics allows fixed position screen resolution (HTML is free
form)

 What I would like to know is whether there is a standard where the location
of the screen objects can be fixed X & Y is a window, and that standard is
the one which will likely become the recommendation.

Best regards and many thanks - Trevor Croll