I recently changed the translatable strings for my application's QActions to use an ellipsis (…) rather than three periods (...).  I was surprised to see that the buttons created by adding these actions to a QToolBar now show the ellipsis in their text, where previously the three periods were suppressed.  I think that the treatment of QActions should be the same for an ellipsis as for three periods (suppressed in toolbar buttons, expressed in menu items).  There might be i18n considerations here also.