code: protected void onSelectedItemChanged() {
          if (selectedItem == null) {
              anchorLabel();
              getInputWidget().setText("");
          } else {
              getInputWidget().setText(getItemPrinter().print(selectedItem));
              floatLabel();
          }
  
          if (itemChooserListener != null) itemChooserListener.onSelectionChanged(this, selectedItem);
      }
docs: Refreshes the widget state when the selection changes