Null Relationships code trigger

オフライン
I want to use a null relationship tab in Parts to return custom query results from Documents. example:
  • get property from parent form: Parts
  • get Documents where doc.property = parent.property
How would I get this potential code to trigger? Theres no onload grid event for relationship tab. //this.setAttribute("type", "Document"); //this.setProperty("some doc.property", "some parent.property"); //return this.apply();