Tip: In the source editor, the signature of a virtual rule function is:
virtual void rulefunction folder.RFName
Do not add code to the Body block in the source editor of a virtual rule function. If you do, you see error messages if you try to save or to switch to the form-based editor.
In virtual rule functions, the Validity field is set to Action and the Return Type is set to Void. column, select where the rule function can be used (source editor equivalents shown in parentheses: