Content restructuring
The Navigator Panel displays the documents and pages in a tree. The tree can be used for navigation purposes, or it can be used in combination with the Multi-Document Thumbnail Viewer to modify the structure. For example, you can rearrange document page order, or move a page from one document to another.
Your solution integrator may have disabled this feature.
All editing functions that can physically change a document are disabled for PDF documents. You cannot delete pages, split a PDF document, or merge two PDF documents. You can however, reject, move, delete, or add sticky notes to PDF documents.