i did just a few modifications to remove most of the path, note the $remove's

Code:
dialog list {
  title ""
  size -1 -1 100 130
  option dbu
  list 6, 5 5 90 90, sort hsbar vsbar
  list 7, 15 94 70 20
  button "Change Folder", 901, 25 117 50 10
}

on *:dialog:list:*:*:{
  if ($devent == init) {
    set %filesource $getdir
    var %null = $findfile($getdir,*,0,did -a list 6 $remove($1-,$getdir))
    did -z list 6
  }
  if ($devent == sclick) {
    if ($did == 901) {
      if (!%filesource) { set %filesource $getdir }
      set %filesource $sdir(%filesource)
      did -r list 6
      var %null = $findfile(%filesource,*,0,did -a list 6 $remove($1-,%filesource))
      did -z list 6
    }
    if ($did == 6) {
      did -r $dname 7
      did -a $dname 7 $bytes($file($did($dname,6).seltext),b) bytes
      did -a $dname 7 $bytes($file($did($dname,6).seltext),m) mb
    }
  }
  if ($devent == dclick) {
    if (!%filesource) { set %filesource $getdir }
    set %filesource $sdir(%filesource)
    did -r list 6
    var %null = $findfile(%filesource,*,0,did -a list 6 $remove($1-,%filesource))
    did -z list 6
  }
}


Problem im finding is in $getdir (weather by initialisation or by selecting it) it wont show the file sizes now that i have done $remove($1-,$getdir)