How to show dismissed level up gem notification

One of my gem was ready to be levelep up but I had no met the requirements to level it up (it was shown gray). I dismissed the notification. No I fulfill the requirements so how to I bring back the notification to be able to level it up? In the inventory it is no longer gray so I just need the notification back to be able to clicl the plus button.

It shows up on the bottom of your inventory panel if you dismiss it from the right side notification, see the plus sign bottom left http://i.imgur.com/oAej3Xd.jpg