Did you try:
$mw->update;

It sounds like a window manager bug.

Pete said:
Yes, $mw->update; was one of the numerous things I tried, to no avail. I just tried it again with no result. Thanks, though. Perhaps it is indeed an XP bug.

I asked Pete if he had yet found a solution.

Pete said (1/20/03):
Hi - Yes, I did get a solution from Stephen O. Lidie, author of the Perl/TK book, to whom I had sent a plea via e-mail. He suggested using iconify and deiconify, and it worked doubly well for me since the visual result of the deiconify shows that the rather lengthy system command has completed. I like it!

if ($choice eq 'rev_hist') {
    $mw->iconify;
    system($frontpage.' '.$mods_rev_file);
    system('scp2 $rev_hist_file $destination');
    $mw->deiconify;
    return;
[download]

In the midst of a subroutine to which I pass a label-widget reference ($last_action_value_l) I invoke 'system'. Sometimes I call the subroutine from the MainWindow, sometimes from a transient (child?) window of the MainWindow. The iconify/deiconify process above doesen't seem to work for transient windows, so perform appropriate checks:

    my $spec_tl = $last_action_value_l->toplevel();

    ## if $spec_tl signifies a transient window, find its master
    ## and iconify/deiconify it.  Otherwise, ic/deic $spec_tl, which
    ## is the master/toplevel of the $last_action_value_l button.

    my $spec_tl_trans = $spec_tl->transient();
        # "tests" whether $spec_tl is a transient window,
        # saves a ref to its MainWindow if it is.

    ## The "pre-system" iconify
    $spec_tl_trans
        ? $spec_tl_trans->iconify()
        : $spec_tl->iconify();

print STDERR "spec_tl_trans:$spec_tl_trans\n" if $spec_tl_trans;

    my $prob_found = system "$path_of_wp $$dd_con_hr{db_filename}";
    if ( $prob_found ) {
        warn "menu_DD_SuppDB:  xls system prob $!";
        $rc = 'red_40';
    }

    ## The "post-system" deiconify
    $spec_tl_trans
        ? $spec_tl_trans->deiconify()
        : $spec_tl->deiconify();
[download]

update (broquaint): fixed <readmore>