# call with parent window and the (string) XRC id, returns 
# the corresponding window
sub FindByXRCID($$) {
	my ($win, $idname) = @_;
	my $id = Wx::XmlResource::GetXRCID($idname) or 
                die("no $idname in XRC");
	my $ctrl = $win->FindWindow($id) or
		die("window with id \"$idname\" ($id) not found in " .
                  $win->GetName());
	return $ctrl;
}