That's a moral right. With respect to the other rights, they are negotiable under licensing agreements. That's all a matter of negotiations about what the artist would retain and what the museum would acquire.
In fact, there is a considerable amount of misinformation about this. Most people buy paintings from dealers and they have no idea what rights they are buying, if any, when they acquire a work. When people land on the doorstep of the museum and say they would like to donate a painting to us, we don't know what we're accepting. We don't know where the copyright is. We have to assume it's still back with the artist.
That gets us to the problem of orphan works, which we've identified, where we cannot find the artist or we cannot find the estate of the artist, and yet we are legally liable for paying fees or getting permission in order to publicly display a work of art. It's a big problem.