`current_msg_list.get(id)` and `rows.get(id,
current_msg_list.table_name)` are not interchangable in terms of
checking for whether we have a message. The former checks whether
the message is in the current message list while the latter checks
whether the message is in the current message list and currently
rendered. `message_edit.end` only operates on rendered messages.
(imported from commit 203ee612bfd0aa94571dde9b601e948b3c6f6cbb)