I helped a friend put up a chair rail in his house yesterday. It turned out great, except that neither of us knew what to do about where it met the window. Since the window didn't have trim around the outside, the chair rail kind of dead ends without any end piece.
Here's a photo:
Any suggestions on how to finish this? I know it would typically be cut at a 45° bevel, but since it's hollow behind the rail, it wouldn't look right unless it was caulked or spackled.