Marble: kml file loaded but shown only with some maps

Question

I want show .kml file on marble maps. It's load the kml but they are showed only with some maps themes.

My code is:

MarbleWidget *mapWidget = new MarbleWidget();

mapWidget->resize(800,600);
mapWidget->setWindowTitle("CQRLOG DXCC Map");
mapWidget->setMapThemeId("earth/bluemarble/bluemarble.dgml");

mapWidget->model()->addGeoDataFile("/home/tom/projects/Qt/dxcc/dxcc.kml");


mapWidget->setZoom(1200);
GeoDataCoordinates
position(8.545486,53.106076,0.0,GeoDataCoordinates::Degree);
mapWidget->centerOn(position);

mapWidget->show();

For example with "behaim1492" map is shows, with "plain" map it isn't shown. Where I wrong? Any hint?