The selected face shouldn't be painted with the text "This" from the third texture of the material (see in Property region on the right):

There are two UV maps used for the cube mesh, one for the full cube (6 faces), one for the top face alone. The material includes three textures, the two first ones (background colors and white dots) are to be used with the full cube UV map visible in the middle panel, the last one is the text, also visible in the middle panel. Its map is the large square around it.

The selected face keeps receiving the portion of the text it would receive with the full cube map. What's wrong?

Using Blender Internal (2.79).