Since 6.0.1 Marshmallow, Android has had a cool feature whereby you tap the power button twice in quick succession and the camera app will open. It's a handy feature, and one I use reasonably regularly to quickly snap a photo.

However, ever since it was introduced, there's been an issue: if the phone or tablet is unlocked and the power button is double tapped, the device will first lock and then open the camera app, rather than just opening the camera. This behaviour is definitely present in Marshmallow, and we're reasonably certain it was the same for N Developer Preview 2 (DP2), although we can't actually find a device to test on (if you have DP2 and find this isn't the case, let us know in the comments).