For whatever reason, hitting End crashes the editor for me.
Also, the Help menu says nothing on how to activate the block properties thing.
For fun I've recreated all the worlds in SMB3 as well as World e+ from SMA4. :3
Now to go back and actually write in the levels using my SMB3 maps.
By the way, how do I control what levels the "vehicles" send you to? I can't figure it out.