diff --git a/src/tree/insert.c b/src/tree/insert.c
index 6f8ffb5..5f95ada 100644
--- a/src/tree/insert.c
+++ b/src/tree/insert.c
@@ -44,13 +44,14 @@ TR_treeInsert(TR_Tree * this, const void * search, TR_TreeComp comp)
 		TR_TREE_FIND(node, search, found, comp);
 
 		if (found == 0) {
-			// we found an element
-			// as this is insert and not find this will overwrite an existing
-			// value, but return the previous one so that it can be freed if
-			// neccessary.
-			void * data = node->data;
-			node->data = (void *)search;
-			return data;
+			// This differs from tsearch, which is the posix equivalent to
+			// this function in that it will not replace an existing value.
+			// If there is a value for the given key in the tree it will be
+			// retured. It is then up to the caller to handle the situation.
+			// This is used in my http header code to handle multiple value
+			// per header. There it is more useful to get the already existing
+			// tree entry and add the new data.
+			return node->data;
 		} else {
 			// not found
 			if (0 < found) {