Colors Button

    This button allows you to choose the color of text
  in your document among five possible choices :
    usual : this is the usual text color, essentially black.
    user1 : this is the color used to write the word "user1".
    user2 : this is the color used to write the word "user2".
    user3 : this is the color used to write the word "user3".
    user4 : this is the color used to write the word "user4".
To modify these colors, go to the menu :
    Preferences->Couleurs->Couleur utilisateur
then click on a user color : a color chooser opens allowing you to choose the color for it.