diff --git a/src/calibre/gui2/tweak_book/editor/text.py b/src/calibre/gui2/tweak_book/editor/text.py
index fa44587907..e1e9452a03 100644
--- a/src/calibre/gui2/tweak_book/editor/text.py
+++ b/src/calibre/gui2/tweak_book/editor/text.py
@@ -155,7 +155,10 @@ class TextEdit(PlainTextEdit):
         base = self.highlighter.doc_name or None
 
         def get_name(name):
-            return get_recommended_folders(current_container(), (name,))[name] + '/' + name
+            folder = get_recommended_folders(current_container(), (name,))[name] or ''
+            if folder:
+                folder += '/'
+            return folder + name
 
         def get_href(name):
             return current_container().name_to_href(name, base)