public boolean isSelected(String label) {
        try {
            for (WebElement element : getSelectlistbox().findElements(By.tagName("li"))) {
                if (element.getText().equalsIgnoreCase(label)) {
                    if (PrimeSelenium.hasCssClass(element, "ui-state-highlight")) {
                        return true;
                    }
                }
            }
        }
        catch (Exception e) {
            // do nothing
        }
        return false;
    }
Is the input using AJAX "itemUnselect" event?

@return true if using AJAX for itemUnselect
primefaces-selenium/primefaces-selenium-components/src/main/java/org/primefaces/selenium/component/SelectManyMenu.java