If the commands in the Palette's menus (File, etc.) are dimmed, the palette's editor window is probably open.
Therefore, commands such as New Palette and Open Palette are not selectable.
The editor window opens automatically when you select the Colors..., Patterns... or Gradients... commands from the Layout menu. Closing the editor window also closes the Palette window. If you select these commands from the Layout menu, you won't be able to access the pulldown menus within the palettes.
To access these commands, you must tear off the palette from the icon.