[apparmor] Thunderbird profile - Links in GNOME

[u]

Hi,

I've added the patch by Douglas Bagnall here:
https://code.launchpad.net/~u-d/apparmor-profiles/+git/apparmor-profiles/+ref/thunderbird/links

Then I thought I need to try to make this work on a Debian/GNOME system
too.  Thunderbird seems to ask gnome-open for my preferred browser but
it does not open links using gnome-open, instead it wants to open the
browsers directly.

But I keep running into this kind of problem when I tell Thunderbird to
use Chromium:

type=AVC msg=audit(1489921484.684:12657): apparmor="DENIED"
operation="file_mmap" profile="icedove//sanitized_helper"
name="/lib/x86_64-linux-gnu/libpthread-2.19.so" pid=32115
comm="chrome-sandbox" requested_mask="m" denied_mask="m" fsuid=0 ouid=0

And when I tell it to use Firefox-ESR:

type=AVC msg=audit(1489921598.610:12721): apparmor="DENIED"
operation="exec" profile="icedove"
name="/usr/lib/firefox-esr/firefox-esr" pid=32303 comm="icedove"
requested_mask="x" denied_mask="x" fsuid=1000 ouid=0

This seems to be a very similar issue here:
https://bugs.launchpad.net/ubuntu/+source/apparmor/+bug/1282314

I was wondering how to solve this.

Cheers!
ulrike