diff --git a/src/gui/widgets/timeline/header-container.hpp b/src/gui/widgets/timeline/header-container.hpp
index 3a6d43065..501d2eaa4 100644
--- a/src/gui/widgets/timeline/header-container.hpp
+++ b/src/gui/widgets/timeline/header-container.hpp
@@ -27,7 +27,7 @@
 #ifndef HEADER_CONTAINER_HPP
 #define HEADER_CONTAINER_HPP
 
-#include <gtkmm.h>
+#include "../../gtk-lumiera.hpp"
 #include <vector>
 
 namespace lumiera {
diff --git a/src/gui/widgets/timeline/track.hpp b/src/gui/widgets/timeline/track.hpp
index b5f193019..4c1e4938e 100644
--- a/src/gui/widgets/timeline/track.hpp
+++ b/src/gui/widgets/timeline/track.hpp
@@ -26,7 +26,7 @@
 #ifndef TRACK_HPP
 #define TRACK_HPP
 
-#include <gtkmm.h>
+#include "../../gtk-lumiera.hpp"
 
 namespace lumiera {
 namespace gui {