ac4ce26d_1_0_Help____Editor__Appearance__Item
[Description] Select this check box to show color preview icons for the color values. See Changing Color Values in Style Sheets. If this check box is not selected, it is still possible to invoke the color picker and change color values, by choosing the Change color intention action. [Item] 
Show CSS color preview icon in gutter
IntelliJ IDEA 14.1.0 Help :: Editor. Appearance