I think they mean they have windows open in different profiles (profiles, not containers), and want the last active one to pick up links from external apps...
I, for one, would like the last active container to be used.
Interesting. I like the option which Edge gives, which is I select the profile that gets URL opens from outside the browser (my "main work profile") and add site-level exceptions that route certain sites to the right profiles (example: LinkedIn links should open in my personal profile, Demo Server accounts open in the dedicated demo profile).
If I relied on "last active" I would frequently get things opening up in the wrong place just because say, last time I was in a browser I happened to be in a my personal profile, and 30 minutes later, I click a link in work Slack.
Yeah, I can see how that can end up messy, but filtering by url also doesn't always work. To give one example: I may open google docs in different containers because I have several accounts (personal and work). So, if I receive a link to a doc that was shared to me, and open it from the mail client... it won't necessarily end up in the right container. It can end up working fine when you use the menu to open in another container, but on many sites, the original url is redirected to a login page or whatever and opening in another container is not going to be helpful at all because you've now lost the original link you needed to open.
I, for one, would like the last active container to be used.