diff --git a/tryton/common/cellrendererdate.py b/tryton/common/cellrendererdate.py
index 593b7ffdc9..81507952e0 100644
--- a/tryton/common/cellrendererdate.py
+++ b/tryton/common/cellrendererdate.py
@@ -9,9 +9,9 @@ class CellRendererDate(gtk.GenericCellRenderer):
             'text': (gobject.TYPE_STRING, None, 'Text',
                 'Text', gobject.PARAM_READWRITE),
             'foreground': (gobject.TYPE_STRING, None, 'Foreground',
-                'Foreground', gobject.PARAM_READWRITE),
+                'Foreground', gobject.PARAM_WRITABLE),
             'background': (gobject.TYPE_STRING, None, 'Background',
-                'Background', gobject.PARAM_READWRITE),
+                'Background', gobject.PARAM_WRITABLE),
             'editable': (gobject.TYPE_INT, 'Editable',
                 'Editable', 0, 10, 0, gobject.PARAM_READWRITE),
     }
diff --git a/tryton/common/cellrenderertext.py b/tryton/common/cellrenderertext.py
index ea888682d6..673968193d 100644
--- a/tryton/common/cellrenderertext.py
+++ b/tryton/common/cellrenderertext.py
@@ -9,9 +9,9 @@ class CellRendererText(gtk.GenericCellRenderer):
             'text': (gobject.TYPE_STRING, None, 'Text',
                 'Text', gobject.PARAM_READWRITE),
             'foreground': (gobject.TYPE_STRING, None, 'Foreground',
-                'Foreground', gobject.PARAM_READWRITE),
+                'Foreground', gobject.PARAM_WRITABLE),
             'background': (gobject.TYPE_STRING, None, 'Background',
-                'Background', gobject.PARAM_READWRITE),
+                'Background', gobject.PARAM_WRITABLE),
             'editable': (gobject.TYPE_INT, 'Editable',
                 'Editable', 0, 10, 0, gobject.PARAM_READWRITE),
             'xalign': (gobject.TYPE_FLOAT, 'XAlign',