diff --git a/IkiWiki/Plugin/htmltidy.pm b/IkiWiki/Plugin/htmltidy.pm
index 1108aeb89..da77e60f1 100644
--- a/IkiWiki/Plugin/htmltidy.pm
+++ b/IkiWiki/Plugin/htmltidy.pm
@@ -41,6 +41,8 @@ sub checkconfig () {
 sub sanitize (@) {
 	my %params=@_;
 
+	return $params{content} unless defined $config{htmltidy};
+
 	my $pid;
 	my $sigpipe=0;
 	$SIG{PIPE}=sub { $sigpipe=1 };
diff --git a/debian/changelog b/debian/changelog
index 246a89080..87a280ed0 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,6 +1,7 @@
 ikiwiki (3.20110125) UNRELEASED; urgency=low
 
   * editpage: Avoid inheriting internal page types.
+  * htmltidy: Avoid breaking the sidebar when websetup is running.
 
  -- Joey Hess <joeyh@debian.org>  Tue, 01 Feb 2011 21:00:57 -0400