private void selectFirstConfig() {
   if (isConfigListEmpty()) {
     disableDeleteButton();
   } else {
     enableDeleteButton();
     configList.setSelectedIndex(0);
   }
 }
 private boolean isConfigListEmpty() {
   return configList.getItemCount() == 0;
 }
 private void selectLastConfig() {
   int lastIndex = configList.getItemCount() - 1;
   configList.setSelectedIndex(lastIndex);
 }
 private int getSelectedConfigIndex() {
   return configList.getSelectedIndex();
 }
 private String getSelectedConfig() {
   return configList.getItemText(getSelectedConfigIndex());
 }
 private void removeSelectedConfig() {
   configurations.remove(getSelectedConfig());
   configList.removeItem(getSelectedConfigIndex());
 }
 private void addConfig(Configuration configuration) {
   configList.addItem(configuration.getName());
   configurations.put(configuration.getName(), configuration);
 }