OKAY ... thank you for the advice to use strict (which is in the original code for this extracted example). I have modified this example code with the appropriate lines. It still works in the same undesired manner. Any hints towards what the real issue is?
#!/usr/local/bin/perl -w
use strict;
use Tk;
my $line = "";
my $submain = MainWindow->new();
my $status = $submain->Button(-text => 'Click to Clear',
-command => sub {$submain->destroy;}
);
$status->pack;
my $text1 = $submain->Text ('-width'=>100, 'height'=>20);
$text1->pack(-side => 'left', -fill => 'y');
$text1->insert('end', "start\n");
$text1->pack;
for(my $loop=0; $loop <= 3; $loop++ )
{
sleep 1;
print "$loop\n";
if ( $loop == 1 ) { $line = "$loop case 1\n"; }
elsif ( $loop == 2 ) { $line = "$loop case 2\n"; }
else { $line = "$loop something else\n"; }
$text1->insert('end', "$line");
$text1->pack;
}
MainLoop();