Clicked event on GtkButton

[Mahesh Chaudhari <mahesh chaudhari ymail com>]

Does it make any difference, generating "clicked" event using mouse click OR gtk_button_clicked() call
My clicked event callback rightly changes background colour when clicked using mouse however change does not 
reflect when the event is generated using gtk_button_clicked() with following code :

Gtkwidget *button1;
void click_button1(GtkWidget *widget, gpointer data)
{
  GdkColor color;
  color.red = 27000;
  color.green = 30325;
  color.blue = 34181;
  gtk_widget_modify_bg(button1, GTK_STATE_NORMAL, &color);
  gtk_widget_show_now(GTK_BUTTON(button1));
}


Any Clue ?