Controlling Folders
Folders give structure to layers, which is especially important if you’re
working on demanding compositions. Folders are often collapsed, so you
can’t see the contents at first sight. This conserves space but it’s not always
desirable. If you want nested layers to reveal their contents and offer a
quick overview, hold the Control/Command key and click on one of the
triangles to expand. All folders at the first level will expand. You can
collapse them again using the same trick. To expand all nested folders
inside the folders as well, hold the Alt/Option key as well as the
Control/Command key.
Hold the Control/Command key to expand the folder.