I was able to fin this. Any way I can put it into Stencyl?
Mouse lock:
A new mouseLock property has been added to Stage. To enable mouse locking set Stage.mouseLock to true. There are several rules which are applied here:
This property can only be set in full screen mode.
It dispatches a runtime exception if it is called in non-full screen mode.
On mobile settings this property always throws an exception. The reason is simple: This feature can only work with a mouse typeof devices and mobile devices do not have such a thing.
The property can be read in non-full screen mode. This allows developers to easily dispatch to alternative input methods if mouse locking is disabled externally for some reason.
When exiting full screen mode Stage.mouseLock is automatically set to false. Note that while in full screen mode mouse event listeners attached to other display objects but the stage will not be dispatched.
In other words to receive mouse deltas and any other mouse event while mouseLock is active you need to attach your mouse event listeners to the stage.
Relative mouse coordinates - New properties (movementX and movementY) on MouseEvent:
http://www.bytearray.org/?p=3755