diff --git a/livesupport/src/modules/widgets/include/LiveSupport/Widgets/ZebraTreeView.h b/livesupport/src/modules/widgets/include/LiveSupport/Widgets/ZebraTreeView.h
index 6dce58e8e..df6f0a397 100644
--- a/livesupport/src/modules/widgets/include/LiveSupport/Widgets/ZebraTreeView.h
+++ b/livesupport/src/modules/widgets/include/LiveSupport/Widgets/ZebraTreeView.h
@@ -217,6 +217,26 @@ class ZebraTreeView : public Gtk::TreeView
                         int*                              mapping)
                                                                 throw ();
 
+        /**
+         *  Event handler for the row_expanded signal.
+         *
+         *  @param  iter    points to the expanded row.
+         *  @param  path    points to the expanded row.
+         */
+        void
+        onRowExpanded(const Gtk::TreeModel::iterator &  iter,
+                      const Gtk::TreeModel::Path &      path)    throw ();
+
+        /**
+         *  Event handler for the row_collapsed signal.
+         *
+         *  @param  iter    points to the collapsed row.
+         *  @param  path    points to the collapsed row.
+         */
+        void
+        onRowCollapsed(const Gtk::TreeModel::iterator &  iter,
+                       const Gtk::TreeModel::Path &      path)   throw ();
+
 
     public:
         /**
diff --git a/livesupport/src/modules/widgets/src/ZebraTreeView.cxx b/livesupport/src/modules/widgets/src/ZebraTreeView.cxx
index a06645424..96a99ea99 100644
--- a/livesupport/src/modules/widgets/src/ZebraTreeView.cxx
+++ b/livesupport/src/modules/widgets/src/ZebraTreeView.cxx
@@ -69,6 +69,10 @@ ZebraTreeView :: ZebraTreeView(Glib::RefPtr<Gtk::TreeModel>  treeModel)
                                             &ZebraTreeView::onRowDeleted));
     treeModel->signal_rows_reordered().connect(sigc::mem_fun(*this,
                                             &ZebraTreeView::onRowsReordered));
+    this->signal_row_expanded().connect(sigc::mem_fun(*this,
+                                            &ZebraTreeView::onRowExpanded));
+    this->signal_row_collapsed().connect(sigc::mem_fun(*this,
+                                            &ZebraTreeView::onRowCollapsed));
 }
 
 
@@ -510,6 +514,30 @@ ZebraTreeView :: onRowsReordered(const Gtk::TreeModel::Path &      path,
 }
 
 
+/*------------------------------------------------------------------------------
+ *  Event handler for the row_expanded signal.
+ *----------------------------------------------------------------------------*/
+void
+ZebraTreeView :: onRowExpanded(const Gtk::TreeModel::iterator &  iter,
+                               const Gtk::TreeModel::Path &      path)
+                                                                    throw ()
+{
+    renumberRows();
+}
+
+
+/*------------------------------------------------------------------------------
+ *  Event handler for the row_collapsed signal.
+ *----------------------------------------------------------------------------*/
+void
+ZebraTreeView :: onRowCollapsed(const Gtk::TreeModel::iterator &  iter,
+                                const Gtk::TreeModel::Path &      path)
+                                                                    throw ()
+{
+    renumberRows();
+}
+
+
 /*------------------------------------------------------------------------------
  *  Renumber the rows after they have changed.
  *----------------------------------------------------------------------------*/
@@ -527,9 +555,12 @@ ZebraTreeView :: renumberRows(void)                                 throw ()
         Gtk::TreeRow    row = *iter;
         row[modelColumns.rowNumberColumn] = rowNumber++;
 
-        for (it = row.children().begin(); it != row.children().end(); ++it) {
-            Gtk::TreeRow    childRow = *it;
-            childRow[modelColumns.rowNumberColumn] = rowNumber++;
+        if (row_expanded(treeModel->get_path(row))) {
+            for (it = row.children().begin(); it != row.children().end();
+                                                                     ++it) {
+                Gtk::TreeRow    childRow = *it;
+                childRow[modelColumns.rowNumberColumn] = rowNumber++;
+            }
         }
     }
 }