Now I have found "thing" than annoying me. I can't view items on previous technology level in the "production" screen but my worker still create this items. For example I can't see copper coin after iron technology, but my 9 worker are still producing it for me...
 "Heavy Industries"){kind=icon}
 "Super Blue Boy Planet"){kind=icon}
In the research tab there is section "Researched", you can find any using technologies there.