Visitrs enables chatting in the same window regardless of whichever different domain the user is coming from, which serves the purpose "not interrupting the surfing process while chatting or vice versa" well (i guess :). In other implementations like using floating page elements or iframes for chatting, when user moves away from the domain,or opens another link in the same window, chat is interrupted.

I've updated the popup window contents where if popup is blocked, visitor can continue by simple clicking the inner link of the popup. I hope this will help usability.

Thanks for feedback.