$mw->bind('<Left>',          sub { $text->yviewScroll(-1, 'units') } );
    $mw->bind('<Up>',            sub { $text->yviewScroll(-1, 'units') } );
    $mw->bind('<Down>',          sub { $text->yviewScroll( 1, 'units') } );
    $mw->bind('<Right>',         sub { $text->yviewScroll( 1, 'units') } );
    $mw->bind('<Alt-Up>',        sub { $text->yviewScroll(-3, 'units') } );
    $mw->bind('<Alt-Down>',      sub { $text->yviewScroll( 3, 'units') } );
    $mw->bind('<Prior>',         sub { $text->yviewScroll(-1, 'pages') } );
    $mw->bind('<Next>',          sub { $text->yviewScroll( 1, 'pages') } );
    $mw->bind('<MouseWheel>',    [ sub { $text->yviewScroll(-($_[1]/120)*3, 'units') }, Tk::Ev('D') ] );