diff --git a/system/selections.py b/system/selections.py
index 90d4ead..7dabf17 100644
--- a/system/selections.py
+++ b/system/selections.py
@@ -105,9 +105,9 @@ class SelectionTree(gtk.TreeView):
                 i = self.store.insert_after(d, None, (selection.title, selection))
 
     def _update_current_dim(self):
-        if not self._current_dim or not self._current_selection:
-            return
-        id_list = self._current_selection[self._current_dim]
+        id_list = []
+        if self._current_dim and self._current_selection:
+            id_list = self._current_selection[self._current_dim]
         self._identifier_list.set_identifiers(id_list)
 
     # Callbacks
@@ -120,7 +120,7 @@ class SelectionTree(gtk.TreeView):
         i = self.store.get_iter(cursor)
         p = self.store.iter_parent(i)
         if p == None:
-            self._current_selection = None
+            self._current_dim = None
         else:
             self._current_dim = self.store.get_value(p, 0)
             self._current_selection = self.store.get_value(i, 1)
@@ -154,6 +154,8 @@ class IdentifierList(gtk.TreeView):
     def set_identifiers(self, identifiers):
         "Show the list of identifier strings."
         self.store.clear()
-        for e in identifiers:
+        id_list = list(identifiers)
+        id_list.sort()
+        for e in id_list:
             self.store.append((e,))