The information to be shown is normally collected from all agenda
files, the files listed in the variable
org-agenda-files1. If a directory is part of this list,
all files with the extension .org in this directory will be part
of the list.
Thus, even if you only work with a single Org file, that file should
be put into the list2. You can customize
the easiest way to maintain it is through the following commands
iswitchb-like interface to switch to and between Org buffers.
The Org menu contains the current list of files and can be used to visit any of them.
If you would like to focus the agenda temporarily on a file not in this list, or on just one file in the list, or even on only a subtree in a file, then this can be done in different ways. For a single agenda command, you may press < once or several times in the dispatcher (see Agenda dispatcher). To restrict the agenda scope for an extended period, use the following commands:
When working with speedbar.el, you can use the following commands in the Speedbar frame:
 If the value of that variable is not a list, but a single file name, then the list of agenda files will be maintained in that external file.
 When using the dispatcher, pressing
< before selecting a command will actually limit the command to
the current file, and ignore
org-agenda-files until the next