diff --git a/src/gui/gtk-lumiera.hpp b/src/gui/gtk-lumiera.hpp
index 6e0013a2c..ac2bfcc52 100644
--- a/src/gui/gtk-lumiera.hpp
+++ b/src/gui/gtk-lumiera.hpp
@@ -33,6 +33,7 @@
 #include <vector>
 #include <boost/utility.hpp>
 #include <boost/shared_ptr.hpp>
+#include <boost/weak_ptr.hpp>
 #include "../common/util.hpp"
 
 extern "C" {
diff --git a/src/gui/widgets/timeline/timeline-header-container.cpp b/src/gui/widgets/timeline/timeline-header-container.cpp
index e2cd0fe75..e5b58d486 100644
--- a/src/gui/widgets/timeline/timeline-header-container.cpp
+++ b/src/gui/widgets/timeline/timeline-header-container.cpp
@@ -434,7 +434,8 @@ TimelineHeaderContainer::draw_header_decoration(
     lookup_timeline_track(model_track);
   
   // Get the cached header box
-  ASSERT(contains(headerBoxes, timeline_track));  
+  weak_ptr<timeline::Track> ptr(timeline_track);
+  ASSERT(contains(headerBoxes, ptr));  
   const Gdk::Rectangle &box = headerBoxes[timeline_track];
   
   // Paint the box, if it will be visible
@@ -502,7 +503,8 @@ TimelineHeaderContainer::get_expander_button_rectangle(
   shared_ptr<Track> track)
 {
   REQUIRE(track != NULL);
-  ASSERT(contains(headerBoxes, track));  
+  weak_ptr<timeline::Track> ptr(track);
+  ASSERT(contains(headerBoxes, ptr));  
   
   const Gdk::Rectangle &box = headerBoxes[track];
   return Gdk::Rectangle(
diff --git a/src/gui/widgets/timeline/timeline-header-container.hpp b/src/gui/widgets/timeline/timeline-header-container.hpp
index 2ac07ad36..a035e104a 100644
--- a/src/gui/widgets/timeline/timeline-header-container.hpp
+++ b/src/gui/widgets/timeline/timeline-header-container.hpp
@@ -276,7 +276,7 @@ private:
    * need to be perpetually recalculated. This cache is regenerated by
    * the layout_headers method.
    **/
-  std::map<boost::shared_ptr<timeline::Track>, Gdk::Rectangle>
+  std::map<boost::weak_ptr<timeline::Track>, Gdk::Rectangle>
     headerBoxes;
   
   //----- User Interaction State -----//