code:

---

$frm = createobject("kixtart.form")
$frm.caption = "ThreeState"
$chk = $frm.CheckBox("Hello",10,10,100,20)
$chk.ThreeState = true
$frm.Show
$chk.onclick="if $$chk.value=2 $$chk.value=0 endif"
while $frm.visible
    $=execute($frm.Doevents)
loop

---