Element needs some time for template-repeat to render all content, so paper-spinner is used to notify the user to wait.

How can I know that template-repeat has finished so I can turn off the spinner?

And related question: how can inner element "item-details" be selected? Again, template-repeat has to be finished first.

Here's the code I am using:

```
<polymer-element name="item-list">

  <template>
    <paper-spinner active></paper-spinner>

    <template id="repeat_items" repeat="{{ item  in  car.items }}">
         <item-details id="item_details" item="{{item}}"></item-details>
    </template>....

```

This is some simulation of the problem: [plnkr.co](http://plnkr.co/edit/8sePeq2RJesz88dDEcnz?p=preview)

**Edit**

links from research:

[spinner example](https://github.com/ebidel/polymer-gmail/blob/master/index.html)

[why does onmutation disconnect after first mutation?](https://groups.google.com/forum/#!topic/polymer-dev/llfRAC_cMIo)

[polymer-how-to-watch-for-change-in-content-properties](https://stackoverflow.com/questions/24699624/polymer-how-to-watch-for-change-in-content-properties)