I wonder how long cases like this one will keep popping up. I think it is pretty straightforward once proper title is established - you've bought stolen proper

I wonder how long cases like this one will keep popping up. I think it is pretty straightforward once proper title is established - you've bought stolen property, and it is returned to its rightful owner. If you have a problem with that, go after the one who sold you the piece - not the original owners. However, it is somewhat puzzling (though perhaps not surprising, given the scale of the crimes committed!) that we yet haven't got a complete-ish, authoritative-ish catalog of the artworks stolen (or, at least, of dubious title transfer) during the war - a place where one could verify the provenance of any piece of art? Surely, at the time this particular painting was last auctioned, the Polish authorities must have known that they were short a Geldrop, courtesy of the nazis? (Though I suspect organizing such a catalog would be a nightmare of epic proportions.) Perhaps some statute of limitations is in order? Say, cases not settled by May 7th, 2045 (for Europe, the centenary of the nazi capitulation) are moot?