--- a/nbproject/project.xml	Sun Dec 02 18:25:43 2018 +0100
+++ b/nbproject/project.xml	Sun Dec 02 20:17:46 2018 +0100
@@ -45,7 +45,7 @@
             <name>relpipe-tr-validator.cpp</name>
             <c-extensions/>
             <cpp-extensions>cpp</cpp-extensions>
-            <header-extensions/>
+            <header-extensions>h</header-extensions>
             <sourceEncoding>UTF-8</sourceEncoding>
             <sourceRootList>
                 <sourceRootElem>.</sourceRootElem>