Hm... this could be somewhat problematic for me. I prefer to view books as PDF since the vast majority of my collection doesn't view well in markup formats, yet PDF is a relatively terrible input format. Fortunately, I don't do conversions often, but now these two semantically distinct features are using the same model in a conflicting manner. (The list I'd use for one is not the list I'd use for the other.)
I suppose I'll have to deal with it for the time being. Given how frequently you release new versions, I'm sure an elegant solution will appear soon enough

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Going along with your solution, is there a way to override this behavior on a per-book basis? For example: I'd like all but a few specific ebooks to open as PDF by default; these specific ebooks would use a different, individually specified format (EPUB, MOBI, etc).
Again, I greatly appreciate your time and consideration.