I had the same issue (the calendar takes up all of the page horizontally) using the link.
The problem is that the class “category-events” is not called in the body tag. To solve the issue you need to add the “category-events” into the body tag
For example replace the following line in header.php in the thematic folder:
<body class=”<?php thematic_body_class()?> category-events”>
I know, it is not a very good solution but it works…