During my lab tests with CapacityIQ, vShield Zones and Appspeed I haven’t uninstalled all extensions in the vCenter before the destruction of the virtual appliances, so some orphaned entries are shown inside the plugin tabs.
I watched around how I get rid of these entries, and I found the following article in the Malaysia VMware Community Blog: click here
They had the same issue with the Nexus 1000v Plugin. It worked for me too, I only had to select the respective plugin name.
One addition: you have to restart your vCenter service afterwards to accomplish the changes.