Hi George,
 

This is exactly how the oXygen Debugger was implemented :)
http://www.oxygenxml.com/xsl_xslt_debugger.html
In 5.1 we added also support for automatically configuring the debugger
with the information from a scenario (debug scenario action) but the
debugger itself is not scenario based.
George
https://lists.sourceforge.net/lists/listinfo/saxon-help
This is great!
 
But how to use oXygen -- I'll have to revert to the older xdt namespace :(
Then my code will not work with Saxon8.3.
 
 
Dimitre.