diff --git a/src/calibre/gui2/markdown_syntax_highlighter.py b/src/calibre/gui2/markdown_syntax_highlighter.py
index b29311eeb2..821c20ac65 100644
--- a/src/calibre/gui2/markdown_syntax_highlighter.py
+++ b/src/calibre/gui2/markdown_syntax_highlighter.py
@@ -18,7 +18,7 @@ class MarkdownHighlighter(QSyntaxHighlighter):
         'uBold': re.compile('(?P<delim>__)(?P<text>[^_]{2,})(?P=delim)'),
         'Italic': re.compile(r'(?P<delim>\*)(?P<text>[^*]{2,})(?P=delim)'),
         'uItalic': re.compile('(?P<delim>_)(?P<text>[^_]+)(?P=delim)'),
-        'Link': re.compile('(?u)(^|(?P<pre>[^!]))\[.*?\]:?[ \t]*\(?[^)]+\)?'),
+        'Link': re.compile(r'(?u)(^|(?P<pre>[^!]))\[.*?\]:?[ ''\t'r']*\(?[^)]+\)?'),
         'Image': re.compile(r'(?u)!\[.*?\]\(.+?\)'),
         'HeaderAtx': re.compile(r'(?u)^\#{1,6}(.*?)\#*(''\n|$)'),
         'Header': re.compile('^(.+)[ \t]*\n(=+|-+)[ \t]*\n+'),