[DiapDealer]

So it seems that while epubs immediately show up in the Windows MRU after opening them, html files, images and the like don't show up in the MRU until after the epub they were added to has been saved. At least that's how it's working for me. Weird. I thought that since epubs showed up immediately after opening, the other file-types would behave similarly. But at least I finally got something other than an epub to show up in the MRU! So it is indeed just expected Windows behavior (and as such, sometimes unhelpful). Now I can return to completely ignoring those Windows Start-menu/Taskbar jump-lists again!