Mail with MailTags checkbox not enabled
 

I have OF and Mail with Mailtags (both most recent versions) on Snow Leopard.

I am not able to enable the checkbox in Clippings that correspond to "Mail with MailTags". Can anyone shed light on why this can happen and what can fix it?

I followed the instructions here, [url]http://forums.omnigroup.com/showthread.php?t=13906[/url]

but that doesn't seem to work.