my $fctrEntry = $mw->Entry(
    -textvariable     => \$factor,
    -validate         => 'focus',
    -validatecommand  => \&validate,
    #-invalidcommand   => \&invalidate,
    -insertbackground => 'cyan',
    -selectforeground => 'white',
    -selectbackground => 'DarkRed',
    -highlightcolor   => 'cyan',
    -background       => 'black',
    -foreground       => 'white')->grid(
    -row              => $chartrow[2] + 2,
    -column           => 32,
    -columnspan       => 3,
    -sticky           => 'new');

sub validate {
    my $val = shift;
    $val ||= "1.00";
    if ($val !~ /^-?\d{1,2}\.\d\d$/ or $val < -10 or $val > 10) {
	print "Bad! ";
	return 0;
    } else {
	print "Good! ";
	return 1;
    }
}
sub invalidate {
    $factor = sprintf("%.2f", $_[0]);
    print "Validate! $factor ";
}