diff --git a/src/calibre/gui2/markdown_syntax_highlighter.py b/src/calibre/gui2/markdown_syntax_highlighter.py
index b6711fe182..f9f1a56ac5 100644
--- a/src/calibre/gui2/markdown_syntax_highlighter.py
+++ b/src/calibre/gui2/markdown_syntax_highlighter.py
@@ -278,4 +278,4 @@ class MarkdownHighlighter(QSyntaxHighlighter):
 
     def highlightHtml(self, text):
         for mo in re.finditer(self.MARKDOWN_KEYS_REGEX['Html'], text):
-            self.setFormat(mo.start(), mo.end() - mo.start(), self.MARKDOWN_KWS_FORMAT['HTML'])
+            self.setFormat(mo.start(), mo.end() - mo.start(), self.MARKDOWN_KWS_FORMAT['Html'])