Android 5.0 brings with it a big redesign of the notification and Quick Settings area, but there was a seemingly odd quirk in the first developer preview. You could see the notifications when Quick Settings was open, but you couldn't interact. Now you can.
Android 5.0 will collapse the list of notifications if you have a lot of them, but it won't hide them. So the top few will be visible, and now you can tap and swipe down there without closing Quick Settings. It's more convenient than the KitKat and earlier style where quick settings completely hides all the notifications. This is much more convenient and I think should alleviate any concern people had about the new layout.