Omitting the durationfield parameter does not result in "all day" events

The documentation says:
http://extensions.xwiki.org/xwiki/bin/view/Extension/FullCalendar+Application#HReference

durationfield: Field of the class to use as the duration of the event. When not set the events will be "day" events

This does not work for me.
To reproduce:

    {{calendar classname="Blog.BlogPostClass" editable="false" 
         year="2009" month="6" date="1" startfield="publishDate"  /}}

Adding durationfield="" does not work either.
The blog is shown to happen at 12:00 instead of being a full day event.

This seems to happen only on the 2.0-SNAPSHOT.