Clicking on a rank in the GUI will send you a message. If you cannot rankup, or are not on the rank, it will change the item to display the correct deny message in the item's name.

Configurability:
There is a new option in the config under the GUI options called "deny-click-item". This is the item that the rank item will change to when it is displaying a message. Change this to any material. If you don't want the item to change but still want the message to be displayed, you have a few options: 1) Change the config option to "RANK" which will only change the display name. 2) Change the config option to "DISABLE" which will send you a message in chat.