@Dušan, I’m not sure. I haven’t personally visited Prnjavor so you would know better than me. My grandmother upon going back home to visit says its not as diverse but there’s still a variety of cultures there. There were Ukrainains because my grandmother grew up as part of the Ukrainian Catholic church there which was quite influential or so she tells me. The Ukrainian population, like the Polish, decreased after WWII but not as bad I think. 

@”Bernhard “, perhaps but the source I was reading says the majority of the Poles in Bosnia and Herzegovina joined the communist partisans even if not enthusiastically.