Sometimes the error, ArrayIndexOutOfBoundsException, was thrown, this should not occur.

With the use of this code, I was able to remove the necessity for EssentialsX to manage experience.

Previously, clicking an item from the player's inventory, while having the XP Shop UI open, would still run the purchase events.
Currently, I added a check to see if the player is clicking a player's inventory, if true, purchase events will not still run.