Version: 4.05.02
This might arguably not be a bug, but at least it's an inconsistancy, so I'll try filing it as a bug

One nice feature in all value fields is that left-click/drag will change the value. Then if you do not wish to keep the new value, you can right-click to dismiss the change. This does not work in the animation editor if you edit a keyframe's value. Can you please make this work?
While we're at it: Could you please make tab jump to the next field? In this case when editing X and hitting tab, please jump to Y. That would be super awesome!
Thank you,
rou