I was having the same problem. Apparently Esplanade has some bug that causes both sidebars to appear at once if you select one sidebar (that is, you have both the left and right sidebar showing up in your right sidebar).
What fixed this situation for us was to go to Appearance>Theme Options>Design, and in the Custom CSS box, put this code:
#sidebar-right {
width: 100%;
}
That cleared the problem right up.