Predictability is a tad subjective (I'll put consistency part aside for a moment here); e.g. you can think of pdf handling this way: lsix is about images first

Predictability is a tad subjective (I'll put consistency part aside for a moment here); e.g. you can think of pdf handling this way: lsix is about images first and foremost, so it makes sense to hide everything else, including pdfs, which are mostly books and papers and other things that thumbnails would hardly even help with. (This reasoning, however, becomes more brittle once we include videos into equation. Should it be images-only tool, or should it be about anything thumbnailable?)