JW Player in Colorbox not closing properly in Firefox

This works fine in Chrome, Safari and IE8/9, but is breaking in Firefox (15.0.1 and 16). Would really appreciate any help.

This code sits in a block:

<a href='#' id='watch_live' style='width: 263px; height: 225px;'><img src='...some-image...' width='263' height='225' /></a>
<div style='display: none;'>
<div id='live_stream' style='margin: 0 auto; text-align: center;'>
[jwplayer|config=livestream-popup|streamer=rtmp://cp132..etc...]
</div>
</div>

Then a little Javascript in scripts.js controls the appearance of Colorbox with the JWPlayer inside it when the anchor tag is clicked:

$("a#watch_live").colorbox({width:"740px", height:"600px", inline:true, href:"#live_stream"});

When the user closes the Colorbox window by clicking on the little cross (on right the right in the attached image) the Colorbox window closes as it should and the JW Player also stops. In Chrome, Safari and IE8/9 this works as expected. However, in Firefox the Colorbox window closes but the video stream continues to play... so you can't SEE anything (because the Colorbox window containing the JWPlayer have disappeared) but you can still HEAR the video stream playing.

Any ideas how I can fix this?