A:  Here it is:

procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  if button = mbRight then
    WITH Sender AS TControl DO
      WITH ClientToScreen(Point(X,Y)) DO
      BEGIN
        PopupMenu1.PopupComponent := TComponent(Sender);
        PopupMenu1.Popup(X,Y);
      END;
end;
 

Note:  The form's popupMenu property must be empty, or it will popup from everywhere.  If you want the form to be the only place showing the popup, place this method on the form's OnMouseDown event.  If you want the VBX to be the only place, then place it on the VBX's OnMouseDown event, etc.