Previously, when an instance of iceweasel was running,
issuing a command
iceweasel -no-remote .....
meant to open a new instance, not to use the already running one.
Now it seems that this switch means that an instance of iceweasel
launched using it is not to accept 'remote' commands
such as iceweasel  -new-tab | -new-window    http://....
This caused me to open a bug report a few days ago,
that was quickly closed out after I managed to open some
new tabs/windows after a (compared to my normal proceedure)
convoluted launch of iceweasel.
Someone should verify this behaviour experimentally,
or by code inspection, or communication with the appropriate
programmer, and then tweak the documentation (including --help)
of -no-remote appropriately.
Thanks for any consideration, all past and future efforts,
and you patience with me.  :-)

Regards, Dallas E. Legan II / legan@acm.org / aw585@lafn.org
http://isthereanotherquestion.blogspot.com
************************************************************************
"Tekeli-li! Tekeli-li!"
        - "At the Mountains of Madness", H.P. Lovecraft

This explains part of the story and gives the relevant pointers:

https://bugzilla.mozilla.org/show_bug.cgi?id=716361

As explained in comment #6 there, this bug was introduced as a fix to:

https://bugzilla.mozilla.org/show_bug.cgi?id=650078

and broke the case where -ProfileManager was used in conjunction with
-no-remote to launch a new instance. That use case was addressed in

https://bugzilla.mozilla.org/show_bug.cgi?id=716110

which introduces a new flag, -new-instance, to do what -no-remote was
doing before.

The patch (present in 716110 linked above) is pretty simple and it
should be possible to backport it to Wheezy. I am affected by it as
well. Currently I have to launch Iceweasel without -no-remote for the
first instance, and with it for the other instances, in order to get a
similar workflow as before.

Alternatively, Iceweasel can also be patched in Wheezy to undo this commit:

http://hg.mozilla.org/mozilla-central/rev/ba38da32b848

in order to recover the old behaviour of -no-remote.

src:iceweasel has been superseded by src:firefox-esr in version
45.0esr-1 in March 2016. Transitional packages to ease upgrades were
provided in the wheezy, jessie, stretch and buster releases. The
transitional packages have been removed finally before the bullseye
release in August 2021.
After regular security support for buster ended in August 2022 and LTS
support ended in June 2024, I'm closing the remaining bug reports now.

Andreas