diff --git a/src/calibre/gui2/fts/search.py b/src/calibre/gui2/fts/search.py
index ed5857976f..95d0ae8edb 100644
--- a/src/calibre/gui2/fts/search.py
+++ b/src/calibre/gui2/fts/search.py
@@ -606,6 +606,8 @@ class ResultDetails(QWidget):
 
     def render_results(self, results, individual_match=None):
         html = []
+        space_pat = re.compile(r'\s+')
+        markup_pat = re.compile('\x1d')
 
         def markup_text(text):
             count = 0
@@ -615,7 +617,7 @@ class ResultDetails(QWidget):
                 count += 1
                 return '<b><i>' if count % 2 else '</i></b>'
 
-            return re.sub('\x1d', sub, re.sub(r'\s+', ' ', text))
+            return space_pat.sub(' ', markup_pat.sub(sub, text))
 
         ci = self.current_individual_match
         for i, (result, formats) in enumerate(zip(results.result_dicts, results.formats)):