The left side of the Atlas screen shows a list of "folders." Each folder contains places that have been grouped together to make it easier to explore different aspects of the changing sky.
When you click on a folder name, the name is highlighted and the locations in the folder appear in the Places list in the middle of the screen. When you return to the Moon Lab, whatever folder was last showing will be active. Only the places in that folder will be available when you click the Places button. Highlighting "All Folders" in the folder list makes all the places in all the folders available.
