Description of problem:
gnome-sound-properties allows configuration of the "Default Mixer Tracks", but this does not affect which tracks mixer_applet2 (which is present in the system tray by default) controls.  mixer_applet2 has its own configuration - some unification is needed here.

Version-Release number of selected component (if applicable):
gnome-applets-2.24.1-1.fc10.i386

How reproducible:
Always

Steps to Reproduce:
1. Change "Default Mixer Tracks" in gnome-sound-properties
2. Observe that the mixer icon on the taskbar ignores this configuration
  
Actual results:
mixer_applet2 has it's own configuration for which sound card to control.

Expected results:
mixer_applet2 should (by default) follow the configuration in gnome-sound-properties.  It is probably useful to still allow this to be overridden though.

Additional info:
I'm not really clear on that the "Default Mixer Tracks" setting in gnome-sound-properties actually controls - I haven't yet found anything that pays attention to it.