Set icon size on the combobox.

sugar/graphics/combobox.py

@@ -19,6 +19,8 @@ import logging
 import gobject
 import gtk
 
+from sugar.graphics import units
+
 class ComboBox(gtk.ComboBox):
     __gtype_name__ = 'SugarComboBox'    
 
@@ -51,6 +53,7 @@ class ComboBox(gtk.ComboBox):
     def append_item(self, action_id, text, icon_name=None):
         if not self._icon_renderer and icon_name:
             self._icon_renderer = gtk.CellRendererPixbuf()
+            self._icon_renderer.props.stock_size = units.microgrid_to_pixels(3)
             self.pack_start(self._icon_renderer, False)
             self.add_attribute(self._icon_renderer, 'icon-name', 2)