Changes have been made in Git for this ticket:

[mms] Fix message redirection regression in dynamic view (Bug #10859).
Sigh.  This was all tested, and then I went and tried to simplify things
in dynamic view since it didn't support redirecting multiple messages
and that broke things.

So fix this correctly by having dynamic view support redirecting
multiple messages. Also, optimize by passing header/content information
back to allow further manipulation.

  8 files changed, 55 insertions(+), 30 deletions(-)
http://git.horde.org/horde-git/-/commit/03dd213b5af9a5ccb37899801f4692f6944126e3

I can't redirect any message anymore, regardless of the mailbox. The 
IMP_Indices object of the redirect message always contains the INBOX 
=> array(null) structure.