Простейший пример по ссылке http://jsfiddle.net/DBkMe/
remove: function (button) {
delete this._childWidths[Id.get(child)];
this._recalculateSize();
ToolBar.superclass.remove.call(this, button);
}
remove: function (button) {
delete this._childWidths[Id.get(button)];
this._recalculateSize();
ToolBar.superclass.remove.call(this, button);
}