sub on_keypress {
    if ($add_bfe_flag) {
        # only respond to these keys
        my $up = 65362;
        my $down = 65364;
        my $left = 65361;
        my $right = 65363;
        my $enter = 65293;        # emulates mouse button-1
        my $keypad_enter = 65421; # emulates mouse button-3

        # determine which key was pressed
        my $w = shift;
        my $e = shift;
        my $keyval = $e->keyval;

        # get current cursor position (screen coordinates)
        my $d = Gtk2::Gdk::Display->get_default;
        my $s = $d->get_default_screen;
        my @p = $d->get_pointer;  # $p[1] is x, $p[2] is y
        my @screen_point = ($p[1],$p[2]);

        # get current cursor position (window coordinates)
        # because function on_press() uses window coordinates
        @point = @last_point;

        # if the first two parameters are 0 (or FALSE),
        # on_press() will use the third parameter as the
        # button pressed
        given ($keyval) {
            when ($up) {$screen_point[1]--;}
            when ($down) {$screen_point[1]++;}
            when ($left) {$screen_point[0]--;}
            when ($right) {$screen_point[0]++;}
            when ($enter) {on_press(0,0,1);}
            when ($keypad_enter) {on_press(0,0,3);}
            default { }
        }
        # move cursor to proper position (uses screen coordinates)
        $d->warp_pointer($s,@screen_point);
    }
}