Some icons do not appear in the systray

If I enable the systray to all icons...

$ dconf read /desktop/unity/panel/systray-whitelist
['all']

...I see the icon for Deluge, but not for Pidgin, nor XChat, nor Turpial.

I should see them all.

Is there a way to debug this more than "I see it I don't see it"?

Thanks!

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: unity 5.10.0-0ubuntu6
ProcVersionSignature: Ubuntu 3.2.0-24.37-generic-pae 3.2.14
Uname: Linux 3.2.0-24-generic-pae i686
NonfreeKernelModules: nvidia
ApportVersion: 2.0.1-0ubuntu6
Architecture: i386
CompizPlugins: [core,composite,opengl,compiztoolbox,decor,vpswitch,snap,mousepoll,resize,place,move,wall,grid,regex,imgpng,session,gnomecompat,animation,fade,unitymtgrabhandles,workarounds,scale,expo,ezoom,unityshell]
Date: Fri Apr 27 11:41:06 2012
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Beta i386 (20120328)
ProcEnviron:
 LANGUAGE=es_AR:es
 TERM=xterm
 PATH=(custom, user)
 LANG=es_AR.UTF-8
 SHELL=/bin/bash
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)