title: bootstrap 3 dropdowns not visible when used inside panel collapse
body: <p>When using the Split button dropdowns component inside a panel the options is not showing, I tried playing with the z-index but cant get the options to show above the panel edge.</p>
  
  <p>Here is a plunker to demonstrate the problem: <a href="http://plnkr.co/edit/3tLsR3?p=preview" rel="nofollow noreferrer">http://plnkr.co/edit/3tLsR3?p=preview</a></p>
  
  <p>I tried setting the overflow: visible; suggested here  <a href="https://stackoverflow.com/a/11963047/1719181">https://stackoverflow.com/a/11963047/1719181</a> but the dropdown still not showing.</p>
  
  <p>Is there some other css or javascript I can apply to help?</p>