Added prevent default to markAllSeen click.

app/assets/javascripts/app/controllers/widget/online_notification.js.coffee

@@ -77,11 +77,15 @@ class App.OnlineNotificationWidget extends App.Controller
         # insert data
        $( App.view('widget/online_notification')(items: items))
     ).on('shown.bs.popover', =>
+
       # show frontend times
       $('#markAllAsSeen').bind('click', (e) =>
+        e.preventDefault()
         @markAllAsSeen(items)
       );
       @frontendTimeUpdate()
+    ).on('hide.bs.popover', =>
+      $('#markAllAsSeen').unbind('click')
     )
 
   fetch: =>