Hello, everyone !
Now I'm developing a module that's based on the store module and almost completely repeat all the store functionality. So I change all necessary parts (class names, constants, language keys, config file etc.), then of course installing / uninstalling it several times and check all other functionality. Everything works fine, but there's one confusing problem, when I enter to my module home page from the main page as not logged (guest) user, this error appeared: checkAction() fatal error. Unknown action ID: 0.
I don't know where's lying main problem, so if there are some advices or thoughts, please help.