The only one started by Poles in 1919 was Wielkopolskie Uprising, after which Poles regained Poznań area still occupied by Germans.....
What about Polish-Bolshevik war?
Nonsense. The reason why Breslau was handed over to Poles was not because it was once a polish city. Germans consituted a majority in that city at least since the 17/18 th century. Wrocław was handed over to us because Stalin wanted to ensure that Poland would not stray away from the SU in the forseable future. It was certain that Germans would not let us have their land and SU was supposed to be the only guarantee for a "free" and "independent" Poland. The same thing with Stettin.
As for Gdańsk, you cannot talk about history of Poland without mentioning Gdańsk. It is a vital part of our history. However, in 1939 it was as polish as Modern Talking. The only reason why Poles wanted it to be part of their reemerged country was for pure practical reasons: Poland while resetablishing it's new boundaries managed to found itself in a war with virtually every neighbour ( apart from Romania) , and it needed a seaport to trade. Eventually Poles had to built their own sea port, Gdynia, from scratch as the inhabitants of Free city Danzig didn't want to have anything to do with Poland.
So to summarize, in politics all you need is an excuse and power and you can do whatever you want. Germans started a war, lost it and had to face consequences. Wrocław is Polish at least since 3 generations and it doesn't seem to change anytime soon.