This is a very strange issue, and I don't know if this is a Gajim issue
or a Jitsi issue, and is very hard to me explain this issue because I
don't speak english very well.
1.-There are 2 computers, one with Slackware Linux 14.0 and the other
with Windows 7.
2.-The Linux machine have Gajim 0.16-beta2
3.-The Windows machine have Jitsi 2.2.4603.9615
When I send a normal message from Gajim to Jitsi, this not appear, but
if the Jitsi user open the chat window, then if I send another message
(Gajim to Jitsi) then appear.
I don't know if this is a Gajim issue or a Jitsi issue, but when I use
Pidgin(Pidgin to Jitsi), there are no problems. I wrote this in the
Gajim buglist https://trac.gajim.org/ticket/7602
Steps to reproduce
1.- Launch Gajim in Linux machine.
2.- Launch Jitsi in Windows machine.
3.- Send the first message from Gajim to Jitsi.