Content of dropdown list not updated when bound collection is replaced

[ghost]

I use abp-select in a table like this:

<table>
  <tr repeat.for="item of items">
    <!-- some other columns -->
    <td>
      <abp-select
       collection.bind="item.subItems"
       selected-item.bind="item.selectedSubItem">
      </abp-select>
    </td>
  </tr>
</table>

Now the problem is that item.subItems may change (i.e. the entire array gets replaced); but when it does, the content of the dropdown list doesn't change.

By contrast, when I use a regular <select>, it works as expected, i.e. the <option> list get updated when item.subItems changes:

<table>
  <tr repeat.for="item of items">
    <!-- some other columns -->
    <td>
      <select
       value.bind="item.selectedSubItem">
        <option repeat.for="subItem of item.subItems" model.bind="subItem">
          ${subItem.option}
        </option>
      </select>
    </td>
  </tr>
</table>

Am I using <abp-select> incorrectly, or is this a bug?