[Klyde]

The 1s button makes your object one sided;... the outside.
The 2s button makes your object 2 sided; the outside and the inside.
If it is your intention to make a one FACE cube then use the rect or a mesh, and not a cube. If it is your intention to make a cube with 6 independant sides then create 6 rects or 6 meshes. Hope this helps.