diff -r 4591c9791a82 -r e06719b7544d mercurial/hgweb/webcommands.py
--- a/mercurial/hgweb/webcommands.py	Wed Dec 12 22:45:02 2018 +0900
+++ b/mercurial/hgweb/webcommands.py	Thu Dec 13 14:44:54 2018 -0500
@@ -858,7 +858,7 @@
     if 'context' in web.req.qsparams:
         context = parsecontext(web.req.qsparams['context'])
     else:
-        context = parsecontext(web.config('web', 'comparisoncontext', '5'))
+        context = parsecontext(web.config('web', 'comparisoncontext'))
 
     def filelines(f):
         if f.isbinary():