Fixed ColorPicker flickering due to offset

since it sits on the little selection bar
it causes flickering

lib/components/color-picker/color-picker.js

@@ -106,7 +106,7 @@ ColorPicker.prototype.spectrumEvents = function(){
     , down;
 
   function update(e) {
-    var color = self.hueAt(e.offsetY);
+    var color = self.hueAt(e.offsetY - 4);
     self.hue(color.toString());
     self.emit('change', color);
     self._huePos = e.offsetY;