JNDI features may be enabled only for one application

It looks like JNDI works correctly only for one web application .
Steps to reproduce:
1. Try to enable jetty-plus that deploys applications from webapps-plus
2. Put 2 applications to webapps-plus (just a WEB-INF with minimal web.xml, no JNDI references)
3. Restart Jetty
4. The following is shown when second application is started:

2009-03-04 17:06:06.097::WARN: Failed startup of context org.mortbay.jetty.weba
pp.WebAppContext@754fc

javax.naming.NamingException: This context is immutable; remaining name 'env'
at org.mortbay.naming.NamingContext.createSubcontext(NamingContext.java:
434)
at org.mortbay.naming.NamingContext.createSubcontext(NamingContext.java:
517)
at org.mortbay.jetty.plus.webapp.EnvConfiguration.createEnvContext(EnvCo
nfiguration.java:58)
at org.mortbay.jetty.plus.webapp.EnvConfiguration.configureDefaults(EnvC
onfiguration.java:101)
at org.mortbay.jetty.webapp.WebAppContext.startContext(WebAppContext.jav
a:1195)
at org.mortbay.jetty.handler.ContextHandler.doStart(ContextHandler.java:
548)
at org.mortbay.jetty.webapp.WebAppContext.doStart(WebAppContext.java:348
)
at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:
50)
at org.mortbay.jetty.handler.HandlerCollection.doStart(HandlerCollection
.java:151)
at org.mortbay.jetty.handler.ContextHandlerCollection.doStart(ContextHan
dlerCollection.java:156)
at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:
50)
at org.mortbay.jetty.handler.HandlerCollection.doStart(HandlerCollection
.java:151)
at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:
50)
at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:
130)
at org.mortbay.jetty.Server.doStart(Server.java:222)
at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:
50)
at org.mortbay.xml.XmlConfiguration.main(XmlConfiguration.java:982)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.
java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces
sorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.mortbay.start.Main.invokeMain(Main.java:218)
at org.mortbay.start.Main.start(Main.java:564)

The same happens when deploying application via context-s, in this case declaring
<Set name="configurationClasses">
<Array id="plusConfig" type="java.lang.String">
...
</Array>
</Set>

in 2 contexts definition causes the very same bug