diff --git a/docs/src/reference/resources/xsl/pdf-custom.xsl b/docs/src/reference/resources/xsl/pdf-custom.xsl
index 7de82b2546..7efc0e39cb 100644
--- a/docs/src/reference/resources/xsl/pdf-custom.xsl
+++ b/docs/src/reference/resources/xsl/pdf-custom.xsl
@@ -421,13 +421,13 @@
         Callouts
     ################################################### -->
 
-<!-- don't use images for callouts
+<!-- don't use images for callouts -->
     <xsl:param name="callout.graphics">0</xsl:param>
     <xsl:param name="callout.unicode">1</xsl:param>
--->
-<!-- Place callout marks at this column in annotated areas
+
+<!-- Place callout marks at this column in annotated areas -->
     <xsl:param name="callout.defaultcolumn">90</xsl:param>
--->
+
 <!--###################################################
         Misc
     ################################################### -->