Q: Why do tabs sometimes show an orange dot?

Sometimes, you’ll notice that a background tab has an orange dot on it in Edge (or a blue dot in Chrome). If you click on the tab, the dot disappears.

The center tab has an orange dot which is not a part of the site’s FavIcon

Years ago, the dot also used to appear any time the title of a pinned tab changed (because pinned tabs don’t show their titles) but that code was removed in 2018.

Nowadays, web content cannot directly trigger the dot icon (short of showing an alert()) but some sites will draw their own indicator by updating their favicon using JavaScript:

Impatient optimist. Dad. Author/speaker. Created Fiddler & SlickRun. PM @ MSFT '01-'12, and '18-, working on Office, IE, Edge, and Web Protection. My words are my own, I do not speak for any other entity. View more posts