Somewhere to store data across lines?

Issue Summary

Thanks, I love this thing! I am trying to light rows based on whether a column value has changed vs. the row before it. I could create a php-generated field which has a value for 'changed' but it seems VTH cannot see php custom fields. The PHP custom field also has an option for a $static variable that allows you to store data across rows, but I cannot see that either, nor any global variables.

Is there somewhere I could store a flag and check it on the next record?