$ctx->{prev_level} = 0;
$ctx->{root_anchor} = anchor_for($mid);
$ctx->{mapping} = {};
- $ctx->{s_nr} = "$nr+ messages in thread";
+ $ctx->{s_nr} = ($nr > 1 ? "$nr+ messages" : 'only message')
+ .' in thread';
my $rootset = thread_results($ctx, $msgs);