d3.behavior.drag = function() {

  var x = 0,
      y = 0,
      listeners = [],
	  dragit

  function drag() {
    var container = this
        .on("mousedown", mousedown)
}

  function mousedown(d, i) {
	// Pick up on where we left before
	// NOTE: Are regexes necessary?
	var prevtrans = d3.select(this).attr('transform');
	
	d3.select(window)
        .on("mousemove", mousemove)
        .on("mouseup", mouseup);

	if (prevtrans) {
		var reg = prevtrans.match(/translate\((\d+),(\d+)\)/i)
		x = reg[1];
		y = reg[2];
	} else {
		x = 0; y = 0;
	}
	
	// Replace x and y with new coordinates
    dragit = {
      x0: x - d3.event.clientX,
      y0: y - d3.event.clientY,
      target: this,
      data: d,
      index: i
    };
    d3.event.preventDefault();
    window.focus(); // TODO focusableParent
  }

  function mousemove() {
      if (dragit) {
			x = d3.event.clientX + dragit.x0;
			y = d3.event.clientY + dragit.y0;
			dispatch.call(dragit.target, dragit.data, dragit.index);
    }
  }

  function mouseup() {
	d3.select(window)
        .on("mousemove", null)
        .on("mouseup", null);
    if (dragit) {
      mousemove();
      dragit = null;
    }
  }



  function dispatch(d, i) {
    var o = d3.event // Events can be reentrant (e.g., focus).

    d3.event = {
      translate: [x, y]
    };

    try {
      for (var j = 0, m = listeners.length; j < m; j++) {
        listeners[j].call(this, d, i);
      }
    } finally {
      d3.event = o;
    }
  }

  drag.on = function(type, listener) {
    if (type == "drag") listeners.push(listener);
    return drag;
  };

  return drag;
};