DefaultConfigurationBuilder is not reloading its base file

Create a DefaultConfigurationBuilder with this example file master-config.xml :
<?xml version="1.0" encoding="UTF-8" ?>

<configuration>
<header>
<result forceReloadCheck="true"/>
</header>
<system/>
<override>
<properties fileName="webapp-commons.properties" throwExceptionOnMissing="true">
<reloadingStrategy refreshDelay="1000" config-class="org.apache.commons.configuration.reloading.FileChangedReloadingStrategy"/>
</properties>
</override>
</configuration>

A modification to "webapp-commons.properties" is well detected and the file is reloaded.
But if you modify the master-config.xml itself, nothing is reloaded, no event are thrown.