Ask HK: How does Bing Chat knows when I switch tabs?

So, first of all, I know about page visibility API and similar, and I use userscripts that block such behavior, so that it looks like I'm always on focus on the page. But for some reason those scripts and tools apparently don't work on Bing Chat AI. The page knows when I switched tabs and stop sending me the answer.

If you want to test for yourself. Go to bing chat and write a message and asks for the question. When the bot starts writing, switch to some other tab and wait a few seconds, than go back to the previous tab and you will see that the message had stopped during the time you left the tab. I tried to search about this, but aside some post on the ublock subreddit (https://old.reddit.com/r/uBlockOrigin/comments/185j3gg/help_block_visibility_api_for_bing_chat/), I couldn't find any explanation.

I was just curious and wondering if anyone on HK has any idea why/how they are monitoring when I switch tabs?