diff --git a/source/ArmarXGui/gui-plugins/ObserverPropertiesPlugin/widgets/properties/DataFieldPropertiesWidget.h b/source/ArmarXGui/gui-plugins/ObserverPropertiesPlugin/widgets/properties/DataFieldPropertiesWidget.h
index 358b039284a2d6a842553022339bf911226c6198..03772566da000e7f581c21089f47481a58927621 100644
--- a/source/ArmarXGui/gui-plugins/ObserverPropertiesPlugin/widgets/properties/DataFieldPropertiesWidget.h
+++ b/source/ArmarXGui/gui-plugins/ObserverPropertiesPlugin/widgets/properties/DataFieldPropertiesWidget.h
@@ -35,7 +35,7 @@
 #include "../VariantWidget.h"
 #include "PropertiesWidget.h"
 #include <ArmarXCore/observers/variant/DatafieldRef.h>
-
+#include<ArmarXCore/core/services/tasks/PeriodicTask.h>
 namespace armarx
 {
     class PlotterController;