Unhide float2 position controls

When a custom filter parameter is of type float2 Position, its controls appear in the 2D view which is great (I'd love to see that working into other Substance 3D apps too...), but the parameters are hidden in the Substance parameter user interface. This is sometimes impractical because in certain occasions we need to access the coordinate values, like to align positions in straight line, copying positions from one parameter to the other.