Turns out I am a baby, I guess:

Had to take that “I’m not a baby, for the love of Pete, please let me switch between apps” option off because I was switching between apps far too much. While I don’t think I’m quite doing NaNoWriMo, I managed to get in a good session of NaChildrensBookWriMo this evening (2k words or so), all thanks to Writer.app and that blessed preference to not trust the writer in any way, shape, or form.