public void sendTabKey() {
        if (isOnchangeAjaxified()) {
            PrimeSelenium.guardAjax(getInput()).sendKeys(Keys.TAB);
        }
        else {
            getInput().sendKeys(Keys.TAB);
        }
    }
Sends the Tab-Key to jump to the next input. Attention: Pressing tab selects the first suggested value.
primefaces-selenium/primefaces-selenium-components/src/main/java/org/primefaces/selenium/component/AutoComplete.java