Lost mouse parallax with center stage or responsive scaling

I have a simple composition that uses mousemove event to control its timeline and give a parallax effect.

However, it does not work anymore when using either the center stage option or the responsive layout one.

Mouse move event detection area remains the one without options enabled, i.e. 960px wide beginning top-left of browser window.

Could someone help?

The JavaScript is as simple as that:

For Stage.documentReady:

     var step = Math.floor(sym.getDuration()/sym.$('Stage').width());     sym.onMove = function(posX){          timelineControl = Number(posX)*step;          sym.stop(timelineControl);     }

And Stage.mousemove:

     sym.onMove( e.pageX );

I am running Edge Animate 2014.1 either with or without jQuery included.