Jim,
What you really want to do is create a subclass of the textbox and use that instead of the VFP BaseClass Textbox. Then you can put the code in the subclass's InteractiveChange.
>Is there a trick to referencing objects on forms from a procedure located in the main.prg? I'm able to code [formname.objectname.click] and this works, but [formname.objectname.caption="test"] does not. If there is not an easy way to make that work, what I really need is a way to run the same routine from many fields in the InteractiveChange procedure of each field. Don't want to copy it to each field as it changes often.