Minecraft wiki entry for Development_versions, associated text: MC-5722 – Destroying a Daylight Sensor by hand works as quick as with a pickaxe, but only using a pickaxe the item drops.
MC-5777 – Game stop reading clicks when you are clicking very fast.
MC-5788 – Inactive detector rail outputs redstone through block.
MC-5874 – Shift left double-click doesn't work.