org-loop-over-headlines-in-active-region

org-loop-over-headlines-in-active-region is a variable defined in `org.el'.
Its value is

nil

Documentation:
Shall some commands act upon headlines in the active region?

When set to `t', some commands will be performed in all headlines
within the active region.

When set to `start-level', some commands will be performed in all
headlines within the active region, provided that these headlines
are of the same level than the first one.

When set to a string, those commands will be performed on the
matching headlines within the active region. Such string must be
a tags/property/todo match as it is used in the agenda tags view.

The list of commands is: `org-schedule', `org-deadline',
`org-todo', `org-archive-subtree', `org-archive-set-tag' and
`org-archive-to-archive-sibling'. The archiving commands skip
already archived entries.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 24.1 of Emacs.