I just loaded a craft and another one appeared for a second. The one that appeared was Artifitial Gravity 2.0, wich is quite big.
The one that I selected is SeaDragon 1.0, there're are multiple crafts in between in the Load Craft menu, so I'm sure I've click in the right name.
This happens when you enter a wrong value or something in the xml and load another craft in the editor: since the problematic xml file isn’t considered part of the craft, it now belongs to the editor and will just stay there until you exit the editor.
It did the same in SP