Document NodeSet#dup behavior
@@ -50,7 +50,10 @@ static VALUE allocate(VALUE klass)
* call-seq:
* dup
*
- * Duplicate this node set
+ * Duplicate this node set. NOTE: any changes to the duplicated node set will also
+ * alter the original node set, since they are contained in the same document. If you
+ * wish to change a duplicate of a node set, create a new document based on the
+ * node set instead.
*/
static VALUE duplicate(VALUE self)
{
