[Guy Harris <gharris@xxxxxxxxx>]

ronnie sahlberg wrote:
> That was from the packet-... .c patches   resetting tree to NULL to early.
>
> Works now.

I assume that, to achieve the maximum speedup, every dissector would 
need to have the

	if (!proto_field_is_referenced(parent_tree, proto_xxx)) {
		tree = NULL;
		subtree = NULL;
	}

code?

If so, perhaps there can be some sort of standard {routine,macro,...} to 
use at the beginning of a dissector to create the top-level item and do 
the check.  (Also, perhaps the routine should be renamed, to take into 
account the fact that it returns TRUE if either

	1) a field for that protocol is used in the filter expression

or

	2) the tree is visible.)