In order to be able to delete a Behavior from the Behavior List (the Master List of Behaviors), the behavior cannot be in use anywhere in the system.
Please take a look at your Client Documents (for the behaviors associated with your MMPs, IGs, and BSPs) and the Account Behaviors page, and remove the behavior from those pages. Once you do that, you should be able to go back into the Behavior List in the Configuration Reference Libraries, and delete it that behavior by selecting it and clicking on the 'Delete' button.
