GtkWidget::remove_accelerator
void remove_accelerator(
      GtkAccelGroup 
      accel_group
     , int accel_key, GdkModifierType accel_mods); 
    
     remove_accelerator()  is a
     way to remove a single accelerator, defined by its key value and
     GtkModifierType.
    
    
     Note that the accelerator needs to be unlocked before this method
     will work.