[layered mode] Distributed children may end up in the wrong order

[morethanreal]

For example:

<polymer-element name="paidtasks-edit-dialog" attributes="opened errorMessage heading">
  <template>
    <paper-action-dialog id="dialog" heading="{{heading}}">
      <content select="#editor"></content>
        <div class="error-text">{{errorMessage}}</div>
        <paper-button dismissive>cancel</paper-button>
        <paper-button id="saveButton" affirmative>Save</paper-button>
      </paper-action-dialog>
  </template>
</polymer-element>

#editor gets appended to paper-action-dialog so it shows up after .error-text.