diff --git a/src/Slit.hh b/src/Slit.hh
index da527939..4e090e4f 100644
--- a/src/Slit.hh
+++ b/src/Slit.hh
@@ -36,6 +36,7 @@
 #include "FbTk/Timer.hh"
 #include "FbTk/Resource.hh"
 #include "FbTk/XLayerItem.hh"
+#include "Layer.hh"
 
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>