Thanks for the suggestions. There is nothing behind Preference Pane, just a desktop image and browser in lower right corner.

I tried disable SMB sharing, turn WIFI off, delete all shared folders, then reboot, PROBLEM solved... just kidding, same problem. Will try to uninstall some rubbish mac osx app I installed next ...

Also installed Onyx yesterday, did some maintenance and cleaning run, didn't seem to help. I wonder if this is sign of some Mac OSX virus ...