Under Lotus WordPro, each document had tabbed document sections with the tabs running down the right side of a document.  Tabs could be drug or otherwise re-arranged.  Individual tabs could be marked in such a way that they did not print when you printed the entire document.  This was, and still is, the most amazing way of laying out a book, manual, or business document.  You could have one or more "notes" tabs which were blocked from printing and a different tab for each chapter/topic.  If you decided to change topic order, you simply changed the tab order.  No icky-nasty cut&paste errors to deal with.  No breaking of styles, etc.

WordPro also had an MDI interface, which LibreOffice desperately needs to get back to.  On the main menu at the top was a "Window" item.  All documents were open within the single instance of WordPro.  You switch documents by pressing ALT-W then, after the window menu appeared, a digit 1-9.  If more than 9 documents were open at one time (not that likely given the memory of the day) the last entry was "m" for more documents.  Pressing "m" would cause a window with all document names to appear.  You scrolled through the list and hit enter on the one you wanted.  This worked in both Windows and OS/2.

Install a copy of Smartsuite 98 under Wine and see how things worked.  It was way ahead of its time.