diff --git a/multiproject/xdocs/properties.xml b/multiproject/xdocs/properties.xml
index 763c2227..f6385ae1 100644
--- a/multiproject/xdocs/properties.xml
+++ b/multiproject/xdocs/properties.xml
@@ -57,8 +57,12 @@
           <td>
             <p>
               This is the list of file specifications to be included when searching for
-              projects to be processed by the plugin
+              projects to be processed by the plugin.
             </p>
+            <strong>
+              The 'top-level' project that you use to run <code>maven multiproject</code>
+              must not be included in the set of projects to be processed.
+            </strong>
             <p>
               Default value is <code>*/project.xml</code>, that is all project.xml files one
               directory below the base directory