diff --git a/src/calibre/gui2/library.py b/src/calibre/gui2/library.py
index 70f75917be..4737cdadcd 100644
--- a/src/calibre/gui2/library.py
+++ b/src/calibre/gui2/library.py
@@ -404,7 +404,8 @@ class BooksModel(QAbstractTableModel):
         for id in ids:
             mi = self.db.get_metadata(id, index_is_id=True)
             if mi.series is not None:
-                mi.tag_order = self.db.books_in_series_of(id, index_is_id=True)
+                mi.tag_order = { mi.series: self.db.books_in_series_of(id,
+                    index_is_id=True)}
             ans.append(mi)
         return ans