New notifications should invalidate dropdown cache

[Colonel_mortis]

If you have already opened the notification list, but elected not to leave the page, then another notification comes in, the cached notification list should be invalidated so that the new notification can be viewed by the user without them needing to refresh the page. Alternatively, the new notification should in inserted into the existing cached notification box (like how Stack Overflow does it), but I know that could potentially be complicated.

Having to refresh the page to get the notifications when the badge indicates that you can view them there is pretty poor UX.