You can use yview(moveto=>$fract) instead of yviewMoveTo($fract).

Here is a convenience fix for the Perl/Tk Chatterbox Client.
Change sub updChatterbox to:

sub updChatterbox {
    my ($mytopchar, $myposition) = $Chatfield->yview();  # retreive sc
+roll pos
    &Status('Checking for new chat messages...');
    foreach (&getFromServer('chat')) { &printChat("$_"); }
    &Status($status_idle);
    if ($myposition == 1) {
        $Chatfield->yview(moveto=>$myposition);
    }
    else {
        $Chatfield->yview(moveto=>$mytopchar);  # restore scroll pos
    }
}
[download]

This allows you to scroll back and read aged chat without having the client jump to the bottom. No more cutting and pasting!!

Update: If I had bothered to actually pay attention while browsing through the Tk CB code, I would have seen the part about $Chatfield->see('end');
Here is a nicer fix:

    if ($myposition == 1) {
    $Chatfield->yview(moveto=>$myposition);
    }
    else {
        $Chatfield->yview(moveto=>$mytopchar);  # restore scroll pos
    }
[download]

-dystrophy