Comment 6 for bug 403629

Submissions from message sharing are used as suggestions. It is possible for the POT to loose messages, or for POFile to change suggestions, but the shared messages remain. The submission (shared message) continues to exist, but it is not in a POFile. the submission is given a zero sequence to ensure its POPO is compatible with other code that accept it. The submission an be used since we know what the text is, but it cannot be traversed to to see the context in a current POFile.

We want an attribute like .is_traversable on the POPO that returns false when the sequence is zero. Templates that link to the POFile message must check if the submission is traversable.