From BlenderWiki

This panel appears in the Editing Context panel group which is accessed using F9 or clicking button in the Buttons window. This panel can appear several ways depending on the type of object selected.

[edit] Link and Materials (Type Text)

• CU: - Name of the Data Block.
• F - Saves the Data Block even if there are no dependencies of this block.
• OB: - Name of this material type object.
• Material(Mat) - This button specifies which Material index should be referenced, i.e. which Material is active. The first digit indicates the number of indices, the second digit indicates the index number of the active Material.
• New - Create a new Material index. The current Material is updated to include this index. If there was no Material, a new one is created.
• Delete - Remove an index. The current Material is updated to exclude this index.
• Select - Select all elements that have the current index. This works in Edit mode only.
• Deselect - The opposite of Select.
• Assign - Assign the current index to all selected elements. For example, vertices or characters.
• AutoTexSpace - Calculates the texture area automatically, after leaving Edit mode. You can also specify a texture area yourself (in Object mode, in the 3D Window using the T), in which case this option is turned OFF.
• Set Smooth - All selected elements are rendered with smoothly varying normals, if applicable.
• Set Solid - All selected elements are rendered with constant normals, if applicable.