"The behavior you are seeing is the intended default. "

The following code proves what traveler said. I removed exportselection option, and print out its default value, it was 1:

use Tk;
use Tk::ROText;
use XML::Simple;
use Data::Dumper;

use strict;
use warnings;

my $mw = MainWindow->new();
my $f = $mw->Frame(-border => 1)->pack(-side => "left", -fill => "both
+");
my $envs_list;
$envs_list = $f->Scrolled("Listbox", -scrollbars=>"e", -selectmode=>"e
+xtended")->pack(-fill => 'both');
$envs_list->insert("end", "abcd");
$envs_list->insert("end", "abcd");
$envs_list->insert("end", "abcd");
$envs_list->insert("end", "abcd");
print $envs_list->cget('-exportselection');

MainLoop;
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