Q: How should I open documents so that it gets saved under my expose or right-click shortcut menu?

I love app exposé, and use it frequently. I often need to reopen previously opened documents, and Keynote's (and Pages's, Numbers's) exposé shows some documents that I've opened recently at the bottom, but not all. My expected behavior would be that it would list any document I've opened chronologically, but it seems to be random. I've tried opening documents by double-clicking the file, opening using File > Open, opening using Alfred (although I haven't tried with Spotlight) and I can't figure out which method saves that "history." Right-clicking the app icon also shows the same document history.

Does anyone know how to achieve what I'm talking about, or know how Keynote/Pages/Numbers decides what to save in the "open history?"