I just opened a link to a friend's Medium post inside Hangouts, and when I view all running apps (the recent-tasks list), the task with the Medium post in it is my Hangouts rather than a separate Medium window. Opening Medium, it's doing its own thing. Opening Hangouts, it shows the Medium post -- I can't go look at other chats or anything without closing the Medium post I'm reading. This is frustrating, as I might want to switch between typing comments in Hangouts and reading the article (for example).
I would like more generally to stop apps from doing "this sort of thing" if possible (though I expect this isn't possible). When Twitter introduced an in-app browser, I turned that off as fast as I could find the setting -- I want to be able to open links and then switch right back to Twitter, letting the link load in the browser while I read a few more tweets. Hangouts appears not to have introduced any setting to disable this behavior. I've noticed a couple other apps do "this sort of thing" as well, though specific instances slip my mind now; a general solution would be great.
I've checked, and this (new?) behavior in Hangouts is identical on my (Cyanogenmod) phone and my (Samsung) tablet.