If you were right then there would be no border disputes at the ICJ. The UNWRA declared refugees in Gaza are still living in Palestine as it is not part of Egypt, Israel or Jordan. They are internally displaced living on disputed land. In the definition I do not see any inheritance rights to that status by future generations. In 2005 Gaza was given a chance to self govern and in short screwedItUp Royally.
To be fair, Israel has the better claim to this land.