I am currently adding a live chat to my webapp. I got it already finished - now to the problem:

I want the live-chat to "stick" to the down right edge part of my webapplication. I want it to still persist, when there is a route-change for example - so the user can still navigate on the page and still do whatever he wants.

I googled already for modal windows, that "follow", but I cant find any results.

How can I accomplish that behaviour of my live chat? (modal window dialog?) What do I need to search for?