scripting contacts in Mavericks

Some clever person came up with the following script that adds a “copy to clipboard” command to the context menu in Contacts. Click the label of an email address (and there is a similar script for phone numbers) and the context menu pops up with this an an option. It worked fine under Mountain Lion, but Mavericks seems to have broken it. Any insights?

– “using terms from” is necessary to let AppleScript know that these event handlers are terminology that belongs to the Contacts app
using terms from application “Contacts”
– This handler returns the Contacts property for which the plug-in should function
on action property
return “email”
end action property
– This handler returns the name of the plug-in to be displayed in the Contacts property popup menu
on action title
return “Copy to Clipboard”
end action title
– This handler basically tells the Contacts app that this plug-in should be enabled for a given person
on should enable action with theProperty for thePerson
if theProperty is not equal to missing value then
return true
else
return false
end if
end should enable action
– This handler runs when the plug-in is selected from the Contacts property popup menu
on perform action with theProperty for thePerson
– Target the contact from where the plug-in was triggered
tell application “Contacts”
– Retrieve the value of the property that triggered the plug-in
set theValue to value of theProperty
end tell
– Copy the value to the clipboard
set the clipboard to theValue
end perform action
end using terms from