I'm not sure when this problem started because I seldom need to use the gnome gui interface to alsamixer (i.e. mixer_applet2).
I've added the gnome "volume-control" applet to my gnome panel for years, but sometime in the recent past the "mixer" function has vanished. When I right-click on the volume-control applet and then on Open Volume Control, I get the "Sound Preferences" dialog; the same one I get when I click on the System::Preferences::Sound menu item on the gnome panel. In that Sound Preferences dialog I see only the volume control known as "Master" on alsamixer, even though alsamixer shows several of the other usual suspects like PCM, CD, Video, etc. Have any of you gnomes out there got the latest Volume Control applet to display all of the various controls provided by your sound card? Thanks! P.S. If you haven't updated world lately you may not have the latest gnome-2.26 (stable) updates yet.