Pointer down action doesn't seem to propagate the position.

If I fire a `PointerDownAction` with the x and y fields set like this:
```haskell
, _actionX = Just 1000
, _actionY = Just 500
```

When I inspect the mouse down on the JavaScript side all the fields like `pageX`, `clientY` are all set to zero, so the mouse down gets applied to whatever is on the top left.