In the xshd file I have a <span> defined as:
<span etc.>
<begin>??</begin>
<end> </end>
</span>
The idea is to highlight a string of text that begins with "??" and end highlighting at the first space there after.
This does not work and highlighting carries on indefinately. I have also tried using the "singleword" keyword in the begin tag which also did not work.