$.Widget.prototype._setOption.apply(self, arguments);

to this one:

  $.Widget.prototype._setOption.apply(this, arguments);

after this commit:

http://github.com/jquery/jquery-ui/commit/3291d3951ab177cde692f9c763248027b3c5a128

due to error:

TypeError: Result of expression 'this.options' [undefined] is not an object.

reported when calling stuff like:

$('#items').sortable('option',{cursor:'crosshair'});