g_return_val_if_fail (MODEST_IS_MSG_VIEW_WINDOW(win), FALSE);
g_return_val_if_fail (MODEST_IS_DIMMING_RULE (user_data), FALSE);
rule = MODEST_DIMMING_RULE (user_data);
g_return_val_if_fail (MODEST_IS_MSG_VIEW_WINDOW(win), FALSE);
g_return_val_if_fail (MODEST_IS_DIMMING_RULE (user_data), FALSE);
rule = MODEST_DIMMING_RULE (user_data);