diff --git a/doc/en/Gtk/TreeModelFilter.xml b/doc/en/Gtk/TreeModelFilter.xml
index 362af8d1b..0bb521fa6 100644
--- a/doc/en/Gtk/TreeModelFilter.xml
+++ b/doc/en/Gtk/TreeModelFilter.xml
@@ -11,7 +11,7 @@
 in a <see cref="T:Gtk.TreeModel" /> for display.</summary>
     <remarks />
     <example>
-	  <code lang="C#">
+      <code lang="C#">
 using System;
 using Gtk;
 
@@ -81,7 +81,7 @@ public class MyWindow : Window
         }
 }
 	  </code>
-	</example>
+    </example>
     <since version="Gtk# 2.4" />
   </Docs>
   <Base>
@@ -957,7 +957,7 @@ public class MyWindow : Window
       <Docs>
         <summary>Constructor</summary>
         <param name="child_model">a <see cref="T:Gtk.TreeModel" />, the model this object is to filter</param>
-        <param name="root">a <see cref="T:Gtk.TreePath" />, the node to use as the model's root node.</param>
+        <param name="root">a <see cref="T:Gtk.TreePath" />, the node to use as the model's root node, pass null to use the entire child tree model.</param>
         <remarks />
       </Docs>
     </Member>
@@ -1185,4 +1185,4 @@ public class MyWindow : Window
       </Docs>
     </Member>
   </Members>
-</Type>
+</Type>
\ No newline at end of file