code: function() {
              if (this._shimActive) {
                  YAHOO.log('Sizing Shim', 'info', 'DragDropMgr');
                  var s = this._shim;
                  s.style.height = Dom.getDocumentHeight() + 'px';
                  s.style.width = Dom.getDocumentWidth() + 'px';
                  s.style.top = '0';
                  s.style.left = '0';
              }
          }
docs: This method will size the shim, called from activate and on window scroll event
  @private
  @method _sizeShim
  @static