rdelmar's comment helped me understand the reasoning behind it not working. Here is what I did in practice to fix the problem:
I had to drag the header view in storyboard down by where the first responder is. You'll notice you can't actually drag the header view down on the view itself, you'll have to drag the element down from the document outline.
I also had to implement viewForHeaderInSection (returning the header view that I made an outlet) and heightForHeaderInSection.
Every time you want to edit the view via storyboard, you'll have to drag it back up to edit it, then drag it back down so it works correctly.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…