onDragStart won't get fired

Hi

i have a very simple example in which I want the user to choose items from one list and have him drop it in another. Items taken from the list to choose from should not get removed from that list. The code I wrote is fairly simple:

``` javascript
selectedArticlesList.sortable({
group: 'front-page-articles'
});

articlesToChooseFrom.sortable({
group: 'front-page-articles',
drop: false,
onDragStart: function ($item, container, _super) {
console.log('drag start', $item);
$item.clone().insertAfter($item);
_super($item, container);
}
});
```

However I `onDragStart` does not seem to get fired. the console.log is not getting executed.