package require Tk
proc disable-autorepeat  {w} {
    bind $w <Any-KeyPress> {bind %W <KeyPress-%K> {break};bind %W <KeyRelease-%K> {single-key %W %K}}
}
proc single-key {w K} {
    bind $w <KeyPress-$K> [list bind $w <KeyPress-$K> {break} ; bind %W <KeyRelease-$K> {single-key %W %K}]
}
text .t
pack .t
.t insert end "autorepeat is disabled under Windows OS"
disable-autorepeat .t