Ok, new info. If I click in the smaller of the two boxes, I can enter text (apparently) but nothing shows up when I type. If I click save and then go to load, the save does show up and I can click it and load it, but there is no indication that I've selected anything. It also appears that I can name a save "{space}".
Save Dialogue:
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Load Dialogue:
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Oh, and in case it helps: