I've had dealings in the past in order to protect my own designs, and on one occasion prosecute for breach of Design Registration.

I'm no expert but it's clear that this is a hugely complex subject not least because of confusing nomenclature and the fact that many agreements, laws etc are intra-national and not recognised internationally or cannot be enforced without great cost.

There is:

Copyright

Intellectual Property Right

Reproduction Rights

Design Registration (in the UK and often incorrectly called Patenting)

Probably other terms too

Some one has by right as the designer, although one has to prove the design date to be in with a chance, others one can assign or sell and the latter one has to purchase.

Each has different conditions, lasts for different amounts of time, is differently recognised and enforceable.