Hi,
You shouldn't be distracted by the fact that 'it used to work'. Maybe it
did, maybe you were just lucky.
It is hard to see what's happening here. DDD might help you traversing
first_child->next->next. Note that the dissector gets called either with
or without a tree pointer. It's NULL for for packet summary, non-NULL for
packet details (using the output to draw the pane) and non-NULL for
filters(!) to get at the packet details without displaying them. This may
make things more clear when working DDD.
Thanx,
Jaap