With the calendar dialog you can created or open pages. It searches through the wiki database looking for pages wich are titled as a date .When you double click on a certain date, for example 6 june 1981, it will create a page named 1981-06-06.
The lenght of the page title has to be 10 characters long, so 2007-1-1 would be a illegal title. If you create a page by the calendar it will automaticly give it a legal name.