When I found it and played with it, I didn't use the themes. I just played with the templates, photos and holiday info. I have tried now and have not figured it out. Sorry.
Thanks Martin, perhaps the author will respond. I love the program, it's very easy to use, but would like my students to use it, and would be a LOT simpler if they could do a single year's worth of calendar via the themes - which appears to be the point - great find in any event!
This site is a great online calendar tool for juggling life's tasks and events. Create and manage multiple calendars to view individually or on the same page.
http://www.dayviewer.com/