[xp84]

That was exactly the example given in the article, but somehow this isn't what I expected would happen if I click a link in say, my email client or chat program.

I imagined it more like: User clicks link in email program. Email program tells OS: "Here, open https://..." -- OS checks URL scheme registry and selects Firefox, OS brings Firefox to the front and throws the URL at it and says "Open this."

I guess perhaps my naïve way could falls down if the OS accepts URLs from apps that aren't in the foreground, so a random background process could activate any app it wants to steal focus.

[elehack]

Yep. With the solution discussed, as I understand it, the e-mail program just needs to be modified to request a focus token and send it along with the URL request to the browser or the OS browser dispatch service to keep the expected behavior.

This could be abstracted by libraries (e.g. a method in Qt to open a URL in the system browser automatically gets the token) so each application doesn't need to be updated separately, or possibly even OS services.