Loads of website who wants to support their customers have a live chat feature. When we start a live chat it always start in a new window instead of the same tab or a new tab. Is there any security achieved by starting the live chat in a new window?
No, this has nothing to do with security. It is just a design or UX question. I quess opening a new window is a simple way to have the chat persist even if the user navigate away from the page.
Note that many modern single page web apps keep chat boxes inside the original window where they were spawned. Facebook is one example, and I could name a couple of companies customer support chats as well.
So this is unrelated to security.