Widget: this._on delegates using instance.widget() instead of passed element

I have a somewhat complex widget that has multiple drop-down menus that are placed directly under the body tag. I expected to be able to do the following:

this._on(this._menu, {'click button': '_menu_button_click'});

... but this doesn't work and actually causes a good bit of chaos. Every button element in the entire widget (except the desired one) is now bound to

_menu_button_click

. This happens because in

$.Widget.prototype._on

, it only uses the passed element if there's no selector specified. Here's that code:

if ( selector ) {
  instance.widget().delegate( selector, eventName, handlerProxy );
} else {
  element.bind( eventName, handlerProxy );
}

It seems to be that it should be calling

element.delegate

, not

instance.widget().delegate

.

Am I doing something wrong?