Eg when adding an entity we emit an event like
$rootScope.$emit('updateReportingMenu');. The menu then reloads itself and shows possible new menu items. Imagine you add a goal via Ajax, this way the newly created goal will be directly shown in the menu.
The same event could be used to clear the existing list of widgets in
widgetsHelper.getAvailableWidgets and the widget menu in the dashboard. Goal would be, that when this event is triggered, it fetches a list of all available widgets again, and re-renders the dashboard widget.
The event name is not ideal, should be more like
onEntityChange or something. We could rename the event in Piwik 4 to not break anything.