Material Table
The Show Material Table option in the Annotate menu will toggle the display of a table of current material properties in the viewport.
To hide the display of the Material Table re-select the Show Material table option.
Material Table Options
If the Material Table is displayed, you can select Material Table Options from the Annotate menu. A dialog will appear allowing you to customize the location of the table display in the viewports, and customize the data displayed in the table.