I think I've found two shortcomings in the code.

1) Calling a UDF from inside an EXECUTE statement like
code:
$iRC=EXECUTE('$a=CustomUDF($b)')
I do not see any code that analyzes the inside of an EXECUTE statement

2) Assigning UDFs to event triggers in KiXforms like
code:
$form.OnLostFocus='CustomUDF()'
_________________________
There are two types of vessels, submarines and targets.