my @hidden_variables = (qw(db status obsolete), map { "l_$_" } @columns);
my @hidden_nondefault = grep({ $form->{$_} } @hidden_variables);
my $callback = build_std_url('action=list_names', grep { $form->{$_} } @hidden_variables);
my @hidden_variables = (qw(db status obsolete), map { "l_$_" } @columns);
my @hidden_nondefault = grep({ $form->{$_} } @hidden_variables);
my $callback = build_std_url('action=list_names', grep { $form->{$_} } @hidden_variables);