private WebElement getMoveTopButton(final WebElement controls) {
        return controls.findElement(By.cssSelector("button[title='Move Top']"));
    }
Gets the "Move top" button from the given {@link WebElement}

@param controls either the source or target controls for the picklist
@return the "Move top" button
primefaces-selenium/primefaces-selenium-components/src/main/java/org/primefaces/selenium/component/PickList.java