When you try to open it you see only spinning loading indicator.
In Stack Trace:

A Guice error caused by:

Caused by: com.vaadin.data.util.converter.Converter$ConversionException: Unable to convert value of type info.magnolia.ui.framework.message.MessageType to presentation type class java.lang.String. No converter is set and the types are not compatible.

More details:
2013-01-07 13:29:07,439 WARN info.magnolia.ui.framework.event.SimpleEventBus : Exception caught when dispatching event: Guice provision errors:

1) Error injecting constructor, com.vaadin.data.Buffered$SourceException
at info.magnolia.ui.app.messages.MessagesViewImpl.<init>(MessagesViewImpl.java:66)
while locating info.magnolia.ui.app.messages.MessagesViewImpl
while locating info.magnolia.ui.app.messages.MessagesView

1 error
com.google.inject.ProvisionException: Guice provision errors:

1) Error injecting constructor, com.vaadin.data.Buffered$SourceException
at info.magnolia.ui.app.messages.MessagesViewImpl.<init>(MessagesViewImpl.java:66)
while locating info.magnolia.ui.app.messages.MessagesViewImpl
while locating info.magnolia.ui.app.messages.MessagesView

1 error
at com.google.inject.internal.InjectorImpl$4.get(InjectorImpl.java:987)