Given how fragile and experimental Devel::Calltree is reported to be, and assuming that your data isn't any more complex than what you're showing (large assumption, I know), you could try unwrapping them yourself.

#!/usr/bin/perl -w
use warnings;
use strict;

my ($tag, %list);
while (<DATA>){
    next unless /./;

    if (/^(\w+)/){
        $tag = $1;
        next;
    }

    if (/^-- (\w+)/){
        push @{$list{$tag}}, $1;
    }
}

for my $type (@{$list{main}}){
    if ($list{$type}){
        for (@{$list{$type}}){
            print "main $type $_\n";
        }
    }
    else {
        print "main $type\n";
    }
}

__END__
display
-- audit
-- bass

elucent
-- audit
-- check

main
-- display
-- elucent
-- audit
-- check
[download]

Output:

main display audit
main display bass
main elucent audit
main elucent check
main audit
main check
[download]

-- 
I hate storms, but calms undermine my spirits.
 -- Bernard Moitessier, "The Long Way"