The Primary Viewer and Secondary Viewer tabs are confined to the document content area:
Consequently, they cannot be repositioned and pinned like the other panes in the Workflow layout. However, these tabs can be stacked on one another.
To open the Secondary Viewer, click Secondary Viewer on the Workflow ribbon. To close the Secondary Viewer, deselect Secondary Viewer on the Workflow ribbon.
To open the Primary Viewer, click Primary Viewer on the Workflow ribbon. To close the Primary Viewer, deselect Primary Viewer on the Workflow ribbon.
The Primary Viewer and Secondary Viewer tabs contain the Window Position button:
Clicking the Window Position button allows you to select the tab that has focus.