Can I view a PDF's Bookmarks and Page Thumbnails Navigation Panes at the same time? If I can't, can this be make possible? It is a constant source of frustration.
Only one of the navigation panes can be active at any given time, so it's either thumbnails, or bookmarks, and not both at the same time.
No, not possible. You can make a feature request here: Feature Request/Bug Report Form
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