diff --git a/src/calibre/gui2/tag_view.py b/src/calibre/gui2/tag_view.py
index b9c4464c57..f6eac49426 100644
--- a/src/calibre/gui2/tag_view.py
+++ b/src/calibre/gui2/tag_view.py
@@ -785,13 +785,14 @@ class TagsModel(QAbstractItemModel): # {{{
                         try:
                             sk = sort_key(ts)[0]
                         except:
-                            sk = ' '
+                            sk = ts[0]
+
                         if sk != collapse_letter_sk:
                             collapse_letter = upper(ts[0])
                             try:
                                 collapse_letter_sk = sort_key(collapse_letter)[0]
                             except:
-                                collapse_letter_sk = ' '
+                                collapse_letter_sk = collapse_letter
                             sub_cat = TagTreeItem(parent=category,
                                      data = collapse_letter,
                                      category_icon = category_node.icon,