Index: /trunk/src/VBox/Main/idl/VirtualBox.xidl
===================================================================
--- /trunk/src/VBox/Main/idl/VirtualBox.xidl	(revision 31072)
+++ /trunk/src/VBox/Main/idl/VirtualBox.xidl	(revision 31073)
@@ -472,5 +472,5 @@
     </const>
     <const name="Future"     value="99999">
-      <desc>Settings version greater than "1.10", written by a future VirtualBox version.</desc>
+      <desc>Settings version greater than "1.11", written by a future VirtualBox version.</desc>
     </const>
   </enum>
@@ -4009,5 +4009,5 @@
       <desc>
         Type of the session.  If <link to="#sessionState"/> is
-        SessionSpawning or SessionOpen, this attribute contains the
+        Spawning or Locked, this attribute contains the
         same value as passed to the
         <link to="IMachine::launchVMProcess"/> method in the
@@ -12832,6 +12832,6 @@
       <desc>
         Type of this session. The value of this attribute is valid only
-        if the session is currently open (i.e. its <link to="#state" /> is
-        SessionState_SessionOpen), otherwise an error will be returned.
+        if the session currently has a machine locked (i.e. its
+        <link to="#state" /> is Locked), otherwise an error will be returned.
       </desc>
     </attribute>
Index: /trunk/src/VBox/Main/xml/Settings.cpp
===================================================================
--- /trunk/src/VBox/Main/xml/Settings.cpp	(revision 31072)
+++ /trunk/src/VBox/Main/xml/Settings.cpp	(revision 31073)
@@ -9,16 +9,24 @@
  * The code can read all VirtualBox settings files version 1.3 and higher. That version was
  * written by VirtualBox 2.0. It can write settings version 1.7 (used by VirtualBox 2.2 and
- * 3.0) and 1.9 (used by VirtualBox 3.1).
- *
- * Rules for introducing new settings: If an element or attribute is introduced that was not
- * present before VirtualBox 3.1, then settings version checks need to be introduced. The
- * settings version for VirtualBox 3.1 is 1.9; see the SettingsVersion enumeration in
- * src/VBox/Main/idl/VirtualBox.xidl for details about which version was used when.
- *
- * The settings versions checks are necessary because VirtualBox 3.1 no longer automatically
- * converts XML settings files but only if necessary, that is, if settings are present that
- * the old format does not support. If we write an element or attribute to a settings file
- * of an older version, then an old VirtualBox (before 3.1) will attempt to validate it
- * with XML schema, and that will certainly fail.
+ * 3.0) and 1.9 (used by VirtualBox 3.1) and newer ones obviously.
+ *
+ * The settings versions enum is defined in src/VBox/Main/idl/VirtualBox.xidl. To introduce
+ * a new settings version (should be necessary at most once per VirtualBox major release,
+ * if at all), add a new SettingsVersion value to that enum and grep for the previously
+ * highest value to see which code in here needs adjusting.
+ *
+ * Certainly ConfigFileBase::ConfigFileBase() will. Change VBOX_XML_VERSION below as well.
+ *
+ * Once a new settings version has been added, these are the rules for introducing a new
+ * setting: If an XML element or attribute or value is introduced that was not present in
+ * previous versions, then settings version checks need to be introduced. See the
+ * SettingsVersion enumeration in src/VBox/Main/idl/VirtualBox.xidl for details about which
+ * version was used when.
+ *
+ * The settings versions checks are necessary because since version 3.1, VirtualBox no longer
+ * automatically converts XML settings files but only if necessary, that is, if settings are
+ * present that the old format does not support. If we write an element or attribute to a
+ * settings file of an older version, then an old VirtualBox (before 3.1) will attempt to
+ * validate it with XML schema, and that will certainly fail.
  *
  * So, to introduce a new setting:
@@ -27,17 +35,18 @@
  *
  *   2) In the settings reader method, try to read the setting; if it's there, great, if not,
- *      the default value will have been set by the constructor.
- *
- *   3) In the settings writer method, write the setting _only_ if the current settings
+ *      the default value will have been set by the constructor. The rule is to be tolerant
+ *      here.
+ *
+ *   3) In MachineConfigFile::bumpSettingsVersionIfNeeded(), check if the new setting has
+ *      a non-default value (i.e. that differs from the constructor). If so, bump the
+ *      settings version to the current version so the settings writer (4) can write out
+ *      the non-default value properly.
+ *
+ *      So far a corresponding method for MainConfigFile has not been necessary since there
+ *      have been no incompatible changes yet.
+ *
+ *   4) In the settings writer method, write the setting _only_ if the current settings
  *      version (stored in m->sv) is high enough. That is, for VirtualBox 3.3, write it
  *      only if (m->sv >= SettingsVersion_v1_11).
- *
- *   4) In MachineConfigFile::bumpSettingsVersionIfNeeded(), check if the new setting has
- *      a non-default value (i.e. that differs from the constructor). If so, bump the
- *      settings version to the current version so the settings writer (3) can write out
- *      the non-default value properly.
- *
- *      So far a corresponding method for MainConfigFile has not been necessary since there
- *      have been no incompatible changes yet.
  */
 
@@ -204,5 +213,6 @@
 
 /**
- * Constructor. Allocates the XML internals.
+ * Constructor. Allocates the XML internals, parses the XML file if
+ * pstrFilename is != NULL and reads the settings version from it.
  * @param strFilename
  */
@@ -571,5 +581,5 @@
  * set the "sv" member to the required settings version that is to
  * be written. For newly created files, the settings version will be
- * the latest (1.9); for files read in from disk earlier, it will be
+ * the latest (1.11); for files read in from disk earlier, it will be
  * the settings version indicated in the file. However, this method
  * will silently make sure that the settings version is always