diff --git a/vncviewer/Viewport.h b/vncviewer/Viewport.h
index 3895fc7..536fbb2 100644
--- a/vncviewer/Viewport.h
+++ b/vncviewer/Viewport.h
@@ -22,6 +22,8 @@
 
 #include <map>
 
+#include <rfb/Rect.h>
+
 #include <FL/Fl_Widget.H>
 
 class Fl_Menu_Button;