Correct the Polish government along with Hungary and Romania received a letter from the Russian Duma to partition Ukraine
Pomerania is a tricky one, you can say its the punishment Germany gets for invading Poland, destroying Warsawa (around 90%!) and countless other cities, stealing Polands national treasures, forced slave labor, more then 3 million polish killed, many also killed by concentration camps (not including Jews), you get the point I could go on forever.
If Poland ever should take it back
Most people/peoples ancestors that came from the Ukraine part of Kresy where killed or relocated to Silesia. The problem is the crazy Neo-Nazis in Ukraine (oddly most prominent in former eastern Poland/Kresy), even the current government of Ukraine admits theirs a problem. Many people fear them and they will do anything to defend their Bandera idiology (They claim Volyn-Galicia is theirs). They simply will make that area too dangerous and stir trouble to prevent Poles from returning. And even though my ancestors lived here, I think its a bad move until their is no more Banderite fascist around.
If it was that easy to get it back, it would have already been done.