I downloaded a zip file that contains the files for the leaves-and-wombats scenario. However, I the screen with the leaves-and-wombats world fails to appear. There is just the same, empty "Create a new subclass of World" on the screen.
If I use the Open option under the Scenario menu to open the zip file, I get a message saying that the archive that was opened does not seem to contain a Greenfoot project. It tells me to try extracting the contents of the zip. For your reference, the zip is in the Downloads folder of my computer.
Can anyone help out?

