This method is used with a FORM variable to display a previously opened form. Thus the ui.Form.open() method needs to be executed prior to it. It displays the form to the current window:
variable.Display([attributes])
This method accepts one optional parameter which is the display attributes of the form to be displayed. You need to specify the attributes as a quoted character string, they are case insensitive.
CALL form_v.Display("yellow, bold")