Quick question on "non-asserts"

The IPKat has been asked a quick question: perhaps you have the answer. It sometimes happens, usually when an intellectual property dispute is settled by agreement, that the IP rights owner undertakes not to assert his right against the other party to the agreement. In theory the rights owner merely forbears to sue, but in practice it can be said to be a licence. Does any reader of this blog know of any reported cases -- in any jurisdiction -- which turned on whether the non-assert was characterised as a licence or not? If so, can he or she please email the IPKat here and tell him.

Forbears here
Forebears here
Four bears here