Spaces Panel
The Spaces panel provides an innovative feature to define areas within the PDF that makes storing and sorting markups easier and more efficient.
Go to Window > Panels > Spaces or press ALT+S to show the
Spaces panel.
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The Spaces panel toolbar contains tools for adding, editing, manipulating, and deleting Spaces.
Add Space: Creates a new space.
Highlight Spaces: Toggles between showing and hiding existing Spaces.
Edit Spaces: Allows resizing and other editing of existing Spaces.