proc autoscroll { scrollbar first last} {
if {$first <= 0 && $last >= 1} {
grid remove $scrollbar
} else {
grid $scrollbar
}
$scrollbar set $first $last
}
itk_component add viewcryst_scroll {
scrollbar $itk_interior.iscroll \
-command [code $this component treectrlcom yview] \
-orient vertical
}
$itk_component(treectrlcom) configure \
-yscrollcommand [list autoscroll $itk_component(viewcryst_scroll)]
grid $itk_component(treectrlcom) $itk_component(viewcryst_scroll) -sticky nswe