diff --git a/src/gui/widgets/timeline-widget.cpp b/src/gui/widgets/timeline-widget.cpp
index 336c67504..07fd3d6f9 100644
--- a/src/gui/widgets/timeline-widget.cpp
+++ b/src/gui/widgets/timeline-widget.cpp
@@ -299,37 +299,35 @@ TimelineWidget::create_timeline_tracks()
 {
   REQUIRE(sequence != NULL);
   
-  create_timeline_tracks_from_branch(sequence->get_tracks());
+  BOOST_FOREACH(model::Track* child, sequence->get_tracks())
+    create_timeline_tracks_from_branch(child);
 }
 
 void
 TimelineWidget::create_timeline_tracks_from_branch(
-  const std::list<model::Track*>& tracks)
+  model::Track* const model_track)
 {
-  BOOST_FOREACH(model::Track* model_track, tracks)
+  REQUIRE(model_track != NULL);
+  
+  // Is a timeline UI track present in the map already?
+  std::map<model::Track*, timeline::Track*>::const_iterator iterator
+    = trackMap.find(model_track);
+  if(iterator == trackMap.end())
     {
-      ASSERT(model_track != NULL);
-      
-      // Is a timeline UI track present in the map already?
-      std::map<model::Track*, timeline::Track*>::const_iterator iterator
-        = trackMap.find(model_track);
-      if(iterator == trackMap.end())
-        {
-          // The timeline UI track is not present
-          // We will need to create one
-          trackMap[model_track] = 
-            create_timeline_track_from_model_track(model_track);
-        }
-      
-      // Recurse to child tracks
-      create_timeline_tracks_from_branch(
-        model_track->get_child_tracks());
+      // The timeline UI track is not present
+      // We will need to create one
+      trackMap[model_track] = 
+        create_timeline_track_from_model_track(model_track);
     }
+  
+  // Recurse to child tracks
+  BOOST_FOREACH(model::Track* child, model_track->get_child_tracks())
+    create_timeline_tracks_from_branch(child);
 }
 
 timeline::Track*
 TimelineWidget::create_timeline_track_from_model_track(
-  model::Track *model_track)
+  model::Track* const model_track)
 {
   REQUIRE(model_track);
   
diff --git a/src/gui/widgets/timeline-widget.hpp b/src/gui/widgets/timeline-widget.hpp
index 63a185be1..eb70aa45e 100644
--- a/src/gui/widgets/timeline-widget.hpp
+++ b/src/gui/widgets/timeline-widget.hpp
@@ -171,12 +171,12 @@ private:
   
   /**
    * Iterates through a branch of tracks, recursing into each sub-branch
-   * creating UI timeline tracks for each model track, if they don't
+   * creating UI timeline tracks for each model track if they don't
    * already exist in trackMap.
-   * @param list The list of model tracks to interate through.
+   * @param list The parent track of the branch.
    **/
   void create_timeline_tracks_from_branch(
-    const std::list<model::Track*>& list);
+    model::Track* const model_track);
   
   /**
    * Creates a timeline UI track to correspond to a model track.
@@ -185,7 +185,7 @@ private:
    * unreckognised type (this is an error condition).
    **/
   static timeline::Track* create_timeline_track_from_model_track(
-    model::Track *model_track);
+    model::Track* const model_track);
   
   /**
    * Looks up a timeline UI track in trackMap that corresponds to a