final TextArea addPeopleTextArea = new TextArea();
addPeopleTextArea.setVisibleLines(5);
addPeopleTextArea.setCharacterWidth(50);
addPeopleTextArea.getElement().setAttribute("placeholder", PLACE_HOLDER_TEXT);
final UserIdSuggestOracle userIdSuggestOracle = new UserIdSuggestOracle(getUsersInSharingSettingsList()) {
@Override
public List<UserId> getItemsMatchingExactly(String itemString) {
List<UserId> userIds = super.getItemsMatchingExactly(itemString);
if(userIds.isEmpty() && itemString.contains("@")) {
userIds.add(UserId.getUserId(itemString.trim()));