old_contents: /**
   @ngdoc service
   * @name umbraco.services.overlayService
   *
   * @description
   * <b>Added in Umbraco 8.0</b>. Application-wide service for handling overlays.
   */
  (function () {
      "use strict";
  
      function overlayService(eventsService, backdropService) {
  
          function open(overlay) {
  
              var backdropOptions = {};
  
              // set the default overlay position to center
              if(!overlay.position) {
                  overlay.position = "center";
              }
  
              // option to disable backdrop clicks
              if(overlay.disableBackdropClick) {
                  backdropOptions.disableEventsOnClick = true;
              }
  
              overlay.show = true;
              backdropService.open(backdropOptions);
              eventsService.emit("appState.overlay", overlay);
          }
  
          function close() {
              backdropService.close();
              eventsService.emit("appState.overlay", null);
          }
  
          var service = {
              open: open,
              close: close
          };
  
          return service;
  
      }
  
      angular.module("umbraco.services").factory("overlayService", overlayService);
  
  })();
new_contents: /**
   @ngdoc service
   * @name umbraco.services.overlayService
   *
   * @description
   * <b>Added in Umbraco 8.0</b>. Application-wide service for handling overlays.
   */
  (function () {
      "use strict";
  
      function overlayService(eventsService, backdropService) {
  
          var currentOverlay = null;
  
          function open(newOverlay) {
  
              // prevent two open overlays at the same time
              if(currentOverlay) {
                  return;
              }
  
              var backdropOptions = {};
              var overlay = newOverlay;
  
              // set the default overlay position to center
              if(!overlay.position) {
                  overlay.position = "center";
              }
  
              // option to disable backdrop clicks
              if(overlay.disableBackdropClick) {
                  backdropOptions.disableEventsOnClick = true;
              }
  
              overlay.show = true;
              backdropService.open(backdropOptions);
              currentOverlay = overlay;
              eventsService.emit("appState.overlay", overlay);
          }
  
          function close() {
              backdropService.close();
              currentOverlay = null;
              eventsService.emit("appState.overlay", null);
          }
  
          var service = {
              open: open,
              close: close
          };
  
          return service;
  
      }
  
      angular.module("umbraco.services").factory("overlayService", overlayService);
  
  })();
subject: Make sure two overlays can't be open at the same time