diff --git a/reference/dom/domdocument.xml b/reference/dom/domdocument.xml
index 1f88ecee63..ca359f1f9b 100644
--- a/reference/dom/domdocument.xml
+++ b/reference/dom/domdocument.xml
@@ -221,7 +221,11 @@
     <varlistentry xml:id="domdocument.props.formatoutput">
      <term><varname>formatOutput</varname></term>
      <listitem>
-      <para>Nicely formats output with indentation and extra space.</para>
+      <para>
+       Nicely formats output with indentation and extra space.
+       This has no effect if the document was loaded with
+       <varname linkend="domdocument.props.preservewhitespace">preserveWhitespace</varname> enabled.
+      </para>
      </listitem>
     </varlistentry>
     <varlistentry xml:id="domdocument.props.implementation">
@@ -236,7 +240,11 @@
     <varlistentry xml:id="domdocument.props.preservewhitespace">
      <term><varname>preserveWhiteSpace</varname></term>
      <listitem>
-      <para>Do not remove redundant white space. Default to &true;.</para>
+      <para>
+       Do not remove redundant white space. Default to &true;.
+       Setting this to &false; has the same effect as passing <constant>LIBXML_NOBLANKS</constant>
+       as <parameter>option</parameter> to <methodname>DOMDocument::load</methodname> etc.
+      </para>
      </listitem>
     </varlistentry>
     <varlistentry xml:id="domdocument.props.recover">