in osgearth 3.2（the latest developing version）,
I created some featurenodes, modelnodes, labelnodes, and so on in the annotationlayer.
The modelnodes, labelnodes can be picked up, except the featuresnodes.
I compared the codes between 3.1 and 3.2, I found that you changed the base classes of linegroup and linedrawable.
in osgearth 3.1, their base classes are geode and geometry.
but in osgearth 3.2, their base classes are group and drawable.
I don't know if that's what caused it.