The right part of your GUI (with the colored triangle thing) is the color editor. You are not seeing anything happening when you click the color editor toolbar button because the color editor is already open.
If just want lines on the surface, you can run the Contour filter on a surface. You can use the Extract Surface filter to get the external surface of a volume or the Slice filter to get a plane in the middle of the volume. When you run Contour on a surface, you get lines.
