diff --git a/src/calibre/gui2/tweak_book/editor/themes.py b/src/calibre/gui2/tweak_book/editor/themes.py
index 9a4a445f98..3035e04e95 100644
--- a/src/calibre/gui2/tweak_book/editor/themes.py
+++ b/src/calibre/gui2/tweak_book/editor/themes.py
@@ -523,7 +523,7 @@ the color of the blinking cursor.</p>
     Namespace prefixes in XML and constants in CSS
 
 {}
-    Non-breaking spaces/hyphens in HTML
+    Non–breaking\xa0spaces/hyphens in HTML
 
 {}
     Syntax errors such as <this <>