Per another comment it appears that notifications are actually real time and the center column content is not. Clicking on a notification, at least in my case, does not necessarily refresh the center column content. For instant I just clicked on a "XXXX voted for" and it brought me to the content but did not show an updated vote count. When I reloaded the page the vote count changed. 

Seems to me that a click on a notification should bring you to the comment/idea etc and refresh the page without the need to reload the page manually.