title: ExtJS: How to position SplitButton menu relative to SplitButton
body: <p>I have a SplitButton at the bottom of the page and is not visible initially(we need to scroll down to see the bottom). When I scroll to SplitButton, then press arrow button to expand splitbutton's menu, menu appears <strong>under</strong> SplitButton(just as planned),  and then scroll up, <strong>the menu remains on screen</strong>, and it is <strong>positioned relative to window</strong>, not the containing div.
  I tried to initialize menu by passing <strong><em>floating: false</em></strong> to it's config, but in this case menu doesn't expands at all. 
  How can I posision SplitButton's menu to have it <strong>always</strong> under SplitButton?</p>
  
  <p>My ExtJS version is 4.07</p>