sub is_arrayref (_) { ref(shift) eq 'ARRAY' }

given ($selection) {
  when (is_arrayref)   { die "unexpected!" }
  when ([wxID_YES])    { $self->Wx::LogStatus('You pressed: "Yes"'   ) }
  when ([wxID_NO])     { $self->Wx::LogStatus('You pressed: "No"'    ) }
  when ([wxID_CANCEL]) { $self->Wx::LogStatus('You pressed: "Cancel"') }
}