What is the difference between CALL_FORM, NEW_FORM and OPEN_FORM?
CALL_FORM: start a new form and pass control to it. The parent form will be suspended until the called form is terminated. NEW_FORM: terminate the current form and replace it with the indicated new form. The old form’s resources (like cursors and locks) will be released. OPEN_FORM: Opens the indicated new form without suspending or replacing the parent form.