From 3D-Coat Wiki
you will forbid drawing with specular. By choosing the shining sphere icon you will enable drawing in specular channel, however with no additional texture overlaid in the channel. The questionmarked folder means that no extra specular channel texture to be overlaid while drawing has been selected. If the texture is selected, the question-marked folder is changed with a specular texture square. Press on the folder to replace the specular texture for your current material. With the help of Specularity slider you can change the reflective qualities applied while drawing. The hot keys “<” and “>” or mouse wheel (under corresponding adjustments in the “Preferences” menu) allow changing the Specular parameter quickly. The Opacity of specularity slider is responsible for change of transparency applied to reflective qualities. The hot keys “:” and “/” or mouse wheel (under corresponding adjustments in the “Preferences” menu) provide for specular transparency decreasing or increasing.