/**
  * Register and perform the command
  *
  * @param operations_manager OperationsManager where command will be reg'ed
  * @param item Model item to configure
  * @param new_index New value
  */
 public ChangeWaveformIndexCommand(
     final OperationsManager operations_manager, final ModelItem item, final int new_index) {
   this.item = item;
   this.old_index = item.getWaveformIndex();
   this.new_index = new_index;
   operations_manager.addCommand(this);
   redo();
 }
 /**
  * Register and perform the command
  *
  * @param model Model to configure
  * @param operations_manager OperationsManager where command will be reg'ed
  * @param new_color New value
  */
 public ChangePlotBackgroundCommand(
     final Model model, final OperationsManager operations_manager, final RGB new_color) {
   this.model = model;
   this.old_color = model.getPlotBackground();
   this.new_color = new_color;
   operations_manager.addCommand(this);
   redo();
 }