Jim, I don't think it's related to 'z'. Actually in your test it probably just highlighted the second one because it starts a sentence in lowercase.
Are you sure you don't have 'komplesem' in the user dictionary?
More likely though, do you have CheckCompoundWords set true? It should be false for Polish.
Thanks
Jim
-your feedback is helpful to other users, thank you!-your feedback is helpful to other users, thank you!