I've noticed this on self-hosted based IRC webchat apps (Shout IRC, TheLounge IRC), but it's probably not unique to just these apps.
To reproduce:
- [Create a new vanilla profile with no extra addons or settings, optional]
- Go to TheLounge IRC homepage and click to try the demo.
I don't think you even have to click connect to start chatting. - Type google.com into the addressbar, hit enter.
[You'll be asked to confirm if you want to leave the page, click "Leave Page"]
The page will merely refresh, and it will stay on the webchat app. - Type something into the search bar and hit enter
The page will merely refresh, and it will stay on the webchat app.
Same thing if you click a link from your bookmarks toolbar.