What is it?
Display Preferences lets you choose how the sound and sound data will be displayed.

How to use it
Display Preferences has the following three parameters, Waveform, Data, Colors.  There is also panes that show what the current preference settings look like (color Macs only). 

The Waveform popup menu has the choice of Lines and Dots.  Lines will draw the sound connecting all the sample points in a vertical line.  Dots will draw the sound displaying all the sample points as dots in a vertical line.

The Data popup menu has the choice of Samples, Seconds, 60ths, and 1000ths.  This will determine how the sound data in the Controls palette will be displayed (length, selection, loop, etc.).

The Colors popup menu has the choice of Set 1 through 9 and Default.  Selecting a color set will display the colors in the eight color panes for Waveform, Selection, Envelope, and Data.  Selecting Default will display the original colors for that color set.  You can copy and paste a color pane, or copy an entire color set by holding down the option key while you select a new color set.  Only the changes you make to the color set being displayed when you click the OK button will be saved.  Keys 1 through 9 will select color Set 1 through 9, and the zero key will select Default.

Notes
You can double click on any of the color panes and a dialog box will be shown with all of the available colors for the current monitor setting.  When using the Brightness slider, hold down the Option key to move all the sliders equally.