code: function() {
              if (YAHOO.lang.isUndefined(this.cfg.getProperty("xy"))) {
                  // Set CFG XY based on DOM XY
                  this.syncPosition();
                  // Account for XY being set silently in syncPosition (no moveTo fired/called)
                  this.cfg.refireEvent("xy");
                  this.beforeShowEvent.unsubscribe(this._primeXYFromDOM);
              }
          }
docs: Set's the container's XY value from DOM if not already set.
  
  Differs from syncPosition, in that the XY value is only sync'd with DOM if
  not already set. The method also refire's the XY config property event, so any
  beforeMove, Move event listeners are invoked.
  
  @method _primeXYFromDOM
  @protected