For no apparent reason, my OS X 10.9.5 Finder has gone haywire. Whenever I create a new Finder window, the main panel, where the files/folders are usually shown, just shows whatever is beneath it, as if there's nothing there. If you drag any other window over the Finder window, that panel will take on the pixels from the other window -- basically the panel is not drawing itself at all.
See screen shot below. It's all greyed out because that's the overlay from the screen shot functionality -- if you look closely you can see how the background is showing through.
I have no idea how or why this happened. I can't think of anything that triggered it. Any idea how to fix this?
Clue 1: rooting the machine doesn't fix it. But resetting the NVRAM does -- at least immediately. After a few minutes of use after the NVRAM reset, the problem reappears.
Clue 2: Icons and Cover Flow view modes work normally. List and Columns view modes do not -- i.e. they show the behavior noted above.