code: function(iPageX, iPageY) {
          if (iPageX) {
              this.lastPageX = iPageX;
              this.lastPageY = iPageY;
          } else {
              var aCoord = YAHOO.util.Dom.getXY(this.getEl());
              this.lastPageX = aCoord[0];
              this.lastPageY = aCoord[1];
          }
      }
docs: Saves the most recent position so that we can reset the constraints and
  tick marks on-demand.  We need to know this so that we can calculate the
  number of pixels the element is offset from its original position.
  @method cachePosition
  @param iPageX the current x position (optional, this just makes it so we
  don't have to look it up again)
  @param iPageY the current y position (optional, this just makes it so we
  don't have to look it up again)