diff --git a/sources/test/testdpplugin.cpp b/sources/test/testdpplugin.cpp
index 7ad9d4c..8be71f0 100644
--- a/sources/test/testdpplugin.cpp
+++ b/sources/test/testdpplugin.cpp
@@ -18,6 +18,7 @@
 
 #include "testdpplugin.h"
 
+#include <KWindowSystem>
 #include <QtTest>
 
 #include "awtestlibrary.h"