I had an empty highlighting palette which came right before my main custom palette in alphabetical order.

I wanted to get rid of it. Right-clicked on it, selected Delete palette. "My palette" was deleted instead.
In spite of the difficulty telling whether I had actually right-clicked in the right place (see http://community.logos.com/forums/t/26028.aspx), I've tried it several times now and am absolutely certain I was right-clicking on the empty palette and not my good one that I wanted to keep.
The only way I could find to delete that unwanted empty palette was to create a style in it, and then I could delete the palette.