diff --git a/src/plugins/projectexplorer/projectnodes.h b/src/plugins/projectexplorer/projectnodes.h
index a20d518b537a26063b5c39b8663ce18c8e7ea5af..ca7916a491806886ee02a4f2ec318ff316d2485f 100644
--- a/src/plugins/projectexplorer/projectnodes.h
+++ b/src/plugins/projectexplorer/projectnodes.h
@@ -338,6 +338,7 @@ private:
 
     // let project & session emit signals
     friend class ProjectNode;
+    friend class FolderNode;
     friend class SessionNode;
     friend class Node;
 };