'Show Desktop' on launcher crashes compiz for any Gtk-Headerbar app when using any third party Gtk(>=3.14) theme (Xenial/Yakkety)

[Khurshid Alam]

This is happening for any gtk-3.12 theme which has proper support for gtk-headerbar.

How to reproduce on Utopic:

1. sudo apt-get install Numix
2. sudo apt-get install gnome-tweak-tool
3. change Gtk theme to Numix
4. Open any app with Gtk-Headerbar (& NOT directly patched by Ubuntu) like gnome-tweak-tool, gnome-system-log
2. enable show-desktop on unity launcher
3. Click on show-desktop first time. it will show desktop.
4. Click on it again, it crashes compiz & sometimes does not recover from it. Users have to fallback to TTY & force restart lightdm.

The problem also occurs for any headerbar app from Gnom3 ppa (for example gnome-contacts, baobab, gnome-maps).

Attached crash file from /var/crash/compiz.

Note: Compiz on other desktop shell/session works relatively well. For example in Gnome-Flashback-Compiz session it doesn't happen.

[Khurshid Alam (khurshid-alam)]

Noticed same thing on vivid (daily build) as well.

[N1ck 7h0m4d4k15 (nick-athens30)]

Yes,
that is reproducible as per your instructions.
I confirm the bug affects Vivid (15.04) as well.

[Khurshid Alam (khurshid-alam)]

I can now reproduce this with Gtk-3.14 on Vivid as well.

[N1ck 7h0m4d4k15 (nick-athens30)]

This bug is still valid in 15.10 Wily Werewolf.

Attached the relevant compiz crash report.

[Khurshid Alam (khurshid-alam)]

I can reproduce in xenial as well. Tagging

[Khurshid Alam (khurshid-alam)]

I can reproduce this under yakkety as well.