I have a friend who is running Maya 2009 on a Mac.

1. He creates a poly plane and scales it. (in wireframe his manipulator handles are all yellow, in shaded mode, they are all grey).
2. He then creates a poly cube.
3. He assigns a lambert to the cube and changes the color to green. The color swatch shows green but the cube in the viewport stays grey.
4. He then assigns lambert to the poly plane and changes the color..as he changes the color, the plane color updates in the view but so does the cube..they are both the same color. He decides to make the plane red. So in view panel, both plane and cube are red...even though cube is assigned a green lambert.
5. He then renders..in the render, the plane is red and the cube is green.

Is this a problem with his graphics card perhaps? He's tried deleting prefs folder. He's also restared his computer. He's had maya for about 2 weeks I think and has had this problem since day 1.