Google nixes merged tabs in dev version of Chrome for Android
Introduced in Lollipop, merged tabs break out individual Chrome pages amongst other apps when you press the Recents (multitasking) button.
There’s always been a way to turn the feature off, and recently Chrome no longer enabled it as the default behavior when launching Chrome for the first time. Now if you launch the latest update to the Chrome Dev version of the browser, you won’t even see the feature available in the settings.
The story behind the story: Google uses the Chrome Dev channel to test out new features, which are then sent to the beta channel before going live in the stable build. It looks like the same thing is at work here, but instead it’s a feature removal. Google probably has numerous metrics that indicate the merge feature is rarely used, so it’s not worth the resources to maintain active development.