Open popup menu and click Appearance control|Browse... You'll see a browse dialog containing a list of color schemes available at your PC.
Tips
Default color scheme is underlined in the list. Color schemes included in randomize list are shown in bold.
You can select multiple color schemes and include/exclude all selected color schemes from randomize list at once.
To resize the preview pane and color scheme list, point to the divider between them until you get a double arrow, and then drag the divider left or right. Also you may use divider popup menu.
You can resize browse dialog using tick marks at the bottom of the window.
To open browse dialog quickly, double click the Appearance control menu item in the popup menu.