diff --git a/YACReader/width_slider.h b/YACReader/width_slider.h
index 3a7c2570..df5522ff 100644
--- a/YACReader/width_slider.h
+++ b/YACReader/width_slider.h
@@ -2,6 +2,7 @@
 #define WIDTH_SLIDER_H
 
 #include <QWidgetAction>
+#include <QWidget>
 
 class QLabel;
 class QSlider;