Code:
dialog track {
  size -1 -1 104 100
  title "Blah?"
  list 1,30 0 23 101,size
}

On 1:DIALOG:track:INIT:1:{
  dll mdx.dll SetMircVersion $version
  dll mdx.dll MarkDialog $dname mdx SetControlMDX $dname 1 TrackBar vertical autoticks both > bars.mdx
  dll mdx.dll SetBorderStyle $dname 1 windowedge
  did -i $dname 1 1 params $calc(65535 - $vol(master)) 0 65535 1000 10000 65535 0 18
  did -i $dname 1 1 tickfreq 1
}
On 1:DIALOG:track:SCLICK:1:{
  tokenize 32 $did($dname,1,1)
  /vol -v $calc(65535 - $1)
}