<p dir="auto">The dropdown disapear in IE &lt;=9  when use bootstrap with bootstrap theme</p>
<p dir="auto">eg: <a href="http://bootply.com/84998" rel="nofollow">http://bootply.com/84998</a></p>
<p dir="auto">This is a usability issue, but if you read <a href="http://ux.stackexchange.com/questions/55800" rel="nofollow">this post</a>, some people are under the impression that bootstrap behaviour is not ideal, where in fact just a small correction to the HTML code in the docs will solve the issue. (Note, however, that some CSS changes will have to take place so the correct pointer cursor is shown - which seem like the really tricky bit?.)</p>