Cannot delete the old Cisco Temporal Agent in Resources section

[rezaalikhani]

Hi all;

I am using ISE 3.2 Patch 6. I have uploaded newer version of "Cisco temporal Agent" in "Resource" section of Work Centers . Posture and want to delete the older version of it. Although this package does not reference anywhere, ISE refuses the deletion... Please look the following screen capture:

Any ideas?

Thanks

[rezaalikhani]

Found the problem. I was expecting to show the reason of the operation in below right corner of the screen but the reason actually mentioned in the above of the screen: