It _is_ a Bug in Ubuntu, because they do not deliver the Standard-Thunderbird-Version with Lightning includes.
It _is_ a Bug in Ubuntu, because Ubuntus xul-ext-lightning is english-only and not international (localized).
A compatibel Release-Version of Lightning is already available, it is just, that Ubuntu does not include it or offer it.
It _is_ a Bug in Ubuntu, because they do not deliver the Standard- Thunderbird- Version with Lightning includes.
It _is_ a Bug in Ubuntu, because Ubuntus xul-ext-lightning is english-only and not international (localized).
A compatibel Release-Version of Lightning is already available, it is just, that Ubuntu does not include it or offer it.