Created attachment 1798 list of available controls I use OSS4 fron 4front tech instead of alsa. XFCE sound config only sees one device 'mixer' and one control 'RecSelect', even though there are dozens of controls available which are picked up fine by other mixers. My distribution (Arch) had it compiled for alsa originally, I had to recompile it for OSS to even get that, so yes it is compiled with --with-sound=oss I attached the output of 'ossmix' which lists all available controls
Given that Xfce 4.6 will be out soon shipping a new mixer I doubt that this will be worked on. Marking it as WONTFIX. Please check whether the new mixer supports OSSv4 (depends on whether there is a GStreamer backend for it).