diff --git a/sugar/graphics/icon.py b/sugar/graphics/icon.py
index 7912208d..8e36e14b 100644
--- a/sugar/graphics/icon.py
+++ b/sugar/graphics/icon.py
@@ -415,12 +415,12 @@ class CanvasIcon(hippo.CanvasBox, hippo.CanvasItem):
             self.props.fill_color = value.get_fill_color()
             self.props.stroke_color = value.get_stroke_color()
         elif pspec.name == 'fill-color':
-            if not isinstance(value, basestring):
+            if not isinstance(value, basestring) and value is not None:
                 raise TypeError('fill-color must be a string, not %r' % type(value))
             self._buffer.fill_color = value
             self.emit_paint_needed(0, 0, -1, -1)
         elif pspec.name == 'stroke-color':
-            if not isinstance(value, basestring):
+            if not isinstance(value, basestring) and value is not None:
                 raise TypeError('stroke-color must be a string, not %r' % type(value))
             self._buffer.stroke_color = value
             self.emit_paint_needed(0, 0, -1, -1)