OK, so it looks like this happens with every view (Audio, Images, Video, etc.). If I click on a view (not the drop-down arrow), the view highlights and the tree drops down (normal). I close the tree by clicking on the arrow, open Tools/Options without changing any settings, click OK, and then the tree drops down (which I believe shouldn't be happening).
Probably won't be enough information, but I figured I'd give it a chance...