Material Editor > Show End Result

Material Editor menu > Material menu > Show End Result

Show End Result lets you look at the material at the level you're on instead of looking at the end result of all the other maps and settings.

When this button is off, the sample slot shows only the current level of the material. This tool is useful when you are working with compound materials. It would be difficult to see exactly what effect you're creating on a particular level if you didn't have the ability to turn off the display of the other levels.