--- a/plugins/dialogs/amplifyfree/module.h
+++ b/plugins/dialogs/amplifyfree/module.h
@@ -5,6 +5,7 @@
 #include <qlabel.h>
 #include "../../../libgui/CurveWidget.h" 
 #include "../../../libgui/ScaleWidget.h" 
+#include "../../../libgui/CornerPatchWidget.h" 
 #include "../../../libgui/Dialog.h"
 #include <libkwave/DialogOperation.h>
 #include <kintegerline.h>