All commands in the Edit menu, work in two mode :
•Thumbnails mode
•Image mode.

The frontmost window determines which mode is in use. If the frontmost window is displaying a whole image, you are in the “Image mode,” otherwise you are in “Thumbnails mode.”

In Thumbnails mode you may copy and paste thumbnails, and their related data, between catalogs or scrapbooks.

In Image mode you may copy an entire image and paste the selection into other programs.