Bubble shadows don't get drawn correctly when enabling transparency

[Steve Dodier-Lazaro]

When (XFCE compositor's) transparency is enabled while a bubble is displayed, the bubble is circled by plain black in the whole rectangle where it's drawn, instead of the expected shadow. It looks like the opacity of the shadow isn't currently set in this scheme.

The attached screenshot comes from 0.9.18 but the problem occurs in bzr trunk as well.

[Mirco Müller (macslow)]

This looks like a race-condition happening when the composited_changed_handler() is called. This occurs only sometimes... very hard to track down.

[Steve Dodier-Lazaro (sidi)]

It happens every time for me, with the XFCE compositor. Feel free to ping me
on Ayatana if you need some information from me or if you want me to run a
patch.

[David Barth (dbarth)]

It may be a compositor bug or a race condition. The latter, I'd prefer we track and fix during the next development cycle, in order not to potentially introduce regressions with other compositors.

[Hugo Cheung (doramon940316)]

I have the same problem in GNOME fallback mode, but I don't have this problem under Unity 2D.
Here is the screenshot under GNOME fallback mode: http://i.imgur.com/Oui6D.png
I don't understand why this problem does not occur under Unity 2D as the notification both uses notify-osd.
My information:
- Ubuntu 12.04
- Linux 3.2.0-29-generic-pae
- GNOME 3.4.2