I cannot launch multiple times firefox from links in email in kmail

in konqueror file association I have mozilla-firefox command
/usr/bin/firefox %u
advanced option
DCOP registration multiple instance

ls -l /usr/bin/firefox
-rwxr-xr-x 1 root root 5522 Sep 14 14:51 /usr/bin/firefox*

The only thing that works is DCOP registration single instance
but then I can launch firefox only once and kmail becomes inactive (cannot use it again)
until I close firefox

inactive = grey screen because of compiz

$ dcop | grep -i fire
gives nothing

ps -eaf | grep -i dcop
1 0 21:04 ? 00:00:00 dcopserver [kdeinit] --nosid

searched the net, fiddled w/w the %u parameter and dcop registration
I am at a loss
Thanks

kmail windows (advanced configure) is
(Default) Disable focus stealing prevention for Firefox
windowa class
firefox-bin

even that does not prevent loosing the focus to firefox,
and kmail remains inactive.
How do I check the windows class of firefox?
(have installed xwininfo)

PS: konqueror is happy to be launched multiple time
from kmail

solved but cannot explain how
deleted entry for firefox in html file association
tehn created one that i called firefox (even for the application name)
pointing to /usr/bin/firefox %u
chose dcop registration none