Dear Maintainer,

I opened an email from linux-api@vger.kernel.org mailing list,
and when I clicked on '1 more' to see the full list of CCs,
the subwindow containing the email header (From, Subject, To, Cc, Date)
and the subwindow containing the message itself, both started resizing in a loop, tilting.
The email was unreadable.  I was using thunderbird 78.5.1.

I upgraded to 84.0b3 from experimental to see if the bug was fixed, and no luck.

However, when I opened the about page (Alt > Help > About Thunderbird)
to check the exact version that was running,
the bug disappeared and I can't trigger it again.

Before opening that, closing and opening thunderbird didn't solve the issue.
It only happened to me with that email.

The email id is:
Message-ID: <160945467182.2830865.6578267403605057347.stgit@magnolia>
You can find it here:
https://lore.kernel.org/linux-api/160945467182.2830865.6578267403605057347.stgit@magnolia/

Hello Alejandro,

Am 01.01.21 um 00:20 schrieb Alejandro Colomar:

I can't reproduce your described behavior so I've no idea what's going
wrong on your side.

Do you have any AddOn installed that might cause this? Please disable
all AddOns and see if the issue is still existing.

I see you have Apparmor enabled. We had cases were Apparmor did make
some trouble. Please check also if disabling Apparmor has some effect.
The reportbug template does not show if the Apparmor profile for
Thunderbird was active, so please have here a look too.

If the issue is still happen it's very likely it's an upstream issue and
needs get reported on

https://bugzilla.mozilla.org/home

Could you mind filling (or searching for a similar) issue there and
point to the bug report then?

I only had the Dark theme enabled. No extensions.
And since I viewed the 'About thunderbird' page, the issue doesn't
reproduce anymore, so no luck.  If it ever happens again, I'll update
you here.

$ sudo aa-status
apparmor module is loaded.
23 profiles are loaded.
20 profiles are in enforce mode.
   /snap/snapd/10492/usr/lib/snapd/snap-confine

/snap/snapd/10492/usr/lib/snapd/snap-confine//mount-namespace-capture-helper
   /usr/bin/man
   /usr/lib/snapd/snap-confine
   /usr/lib/snapd/snap-confine//mount-namespace-capture-helper
   /usr/lib/x86_64-linux-gnu/lightdm/lightdm-guest-session
   /usr/lib/x86_64-linux-gnu/lightdm/lightdm-guest-session//chromium
   docker-default
   libreoffice-senddoc
   libreoffice-soffice//gpg
   libreoffice-xpdfimport
   libvirtd
   libvirtd//qemu_bridge_helper
   lsb_release
   man_filter
   man_groff
   nvidia_modprobe
   nvidia_modprobe//kmod
   snap-update-ns.android-studio
   virt-aa-helper
3 profiles are in complain mode.
   libreoffice-oopslash
   libreoffice-soffice
   snap.android-studio.android-studio
1 processes have profiles defined.
1 processes are in enforce mode.
   /usr/sbin/libvirtd (590) libvirtd
0 processes are in complain mode.
0 processes are unconfined but have a profile defined.

I didn't find it, I'll report it.

Thanks,

Alex

Hi Carsten,

I forgot to report it then.  I reproduced it again today, so I reported
it just now to their bugzilla:
<https://bugzilla.mozilla.org/show_bug.cgi?id=1746753>

Cheers,
Alex