title: Getting IllegalArgumentException in selenium
body: <p>I executed the below script</p>
  <pre><code>  Actions a1 = new Actions(driver);
    a1.moveToElement(Dropdown).click().keyDown(Keys.SHIFT).keyDown(Keys.ARROW_DOWN).keyDown(Keys.ENTER);
  </code></pre>
  <p>but I am getting the below exception :
  Exception in thread &quot;main&quot; java.lang.IllegalArgumentException: Key Down / Up events only make
  sense for modifier keys.
  How do I solve this ??</p>