As currently we have `onerror` management (thanks for adding it! :) ) I was thinking about using it taking into account that a 'deletion' could trigger an error. So in this case I would create the following:
- `hideMessageFromDOM/showMessageInDOM` methods. This methods let you hide/show a message (taking into account the `header` and `ul`), so if the message deletion is not happening due to an error, we can restore the previous status of DOM
- Call https://github.com/mozilla-b2g/gaia/pull/10898/files#L1R1566 in the `onsuccess`.

Wdyt?