Document "includeOptional" on the site.
diff --git a/src/changes/changes.xml b/src/changes/changes.xml
index 80a9197..96df9b4 100644
--- a/src/changes/changes.xml
+++ b/src/changes/changes.xml
@@ -36,9 +36,12 @@
<action dev="ggregory" type="update" issue="CONFIGURATION-752" due-to="Gary Gregory">
Update Apache Commons VFS from 2.3 to 2.4.
</action>
- <action dev="ggregory" type="update" due-to="Gary Gregory">
+ <action dev="ggregory" type="fix" due-to="Gary Gregory">
Fix Javadoc for org.apache.commons.configuration2.PropertiesConfiguration.getIncludeOptional().
</action>
+ <action dev="ggregory" type="add" due-to="Gary Gregory">
+ Document "includeOptional" on the site.
+ </action>
</release>
<release version="2.5" date="2019-05-23"
description="Minor release with new features and updated dependencies.">
diff --git a/src/site/xdoc/userguide/howto_properties.xml b/src/site/xdoc/userguide/howto_properties.xml
index a4200cb..4461b16 100644
--- a/src/site/xdoc/userguide/howto_properties.xml
+++ b/src/site/xdoc/userguide/howto_properties.xml
@@ -94,8 +94,14 @@
<subsection name="Includes">
<p>
If a property is named "<code>include</code>", and the value of that property is the
- name of a file on the disk, that file will be included into the configuration. Here is
- an example:
+ name of a file on the disk, that file will be included into the configuration.
+ </p>
+ <p>
+ The difference between "<code>include</code>" and "<code>includeOptional</code>" (below) is that if the file value
+ is absent, processing continues with "<code>includeOptional</code>" but stops with "<code>include</code>".
+ </p>
+ <p>
+ For example:
</p>
<source>
# usergui.properties
@@ -112,6 +118,33 @@
</subsection>
+ <subsection name="Oprional Includes">
+ <p>
+ If a property is named "<code>includeOptional</code>", and the value of that property is the
+ name of a file on the disk, that file will be included into the configuration.
+ </p>
+ <p>
+ The difference between "<code>include</code>" (above) and "<code>includeOptional</code>" is that if the file value
+ is absent, processing continues with "<code>includeOptional</code>" but stops with "<code>include</code>".
+ </p>
+ <p>
+ For example:
+ </p>
+<source>
+# usergui.properties
+
+includeOptional = colors.properties
+includeOptional = sizes.properties
+</source>
+
+<source>
+# colors.properties
+
+colors.background = #FFFFFF
+</source>
+
+ </subsection>
+
<subsection name="Lists and arrays">
<p>
As was already pointed out in the section
