code: function( step ) {
              if ( lastEntered !== step ) {
                  lib.util.triggerEvent( step, "impress:stepenter" );
                  lastEntered = step;
              }
              lib.util.triggerEvent( step, "impress:steprefresh" );
          }
docs: `onStepEnter` is called whenever the step element is entered but the event is triggered only if the step is different than last entered step. We sometimes call `goto`, and therefore `onStepEnter`, just to redraw a step, such as after screen resize. In this case - more precisely, in any case - we trigger a `impress:steprefresh` event.