Double click :-

@Test
public void Doubleclick() throws Exception

{
driver.get("
http://seleniumsubbu.blogspot.in/");
Thread.sleep(3000);
Actions act = new Actions(driver);
act.moveToElement(driver.findElement(By.xpath("//*[@id='node-235']/div/div[1]/div/div/button"))).doubleClick().perform();

}