diff --git a/src/controls/QskSubWindowArea.h b/src/controls/QskSubWindowArea.h
index 3cbc30d3..cacd94ea 100644
--- a/src/controls/QskSubWindowArea.h
+++ b/src/controls/QskSubWindowArea.h
@@ -8,7 +8,6 @@
 
 #include "QskControl.h"
 
-class QskGradient;
 class QskSubWindow;
 
 class QSK_EXPORT QskSubWindowArea : public QskControl