为啥window7的firefox下，flash背景半透明失效了？

win7下firefox版本是49.02，flash版本是 23.0.0.205.

html里导入flash的代码如下，

<object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=6,0,29,0" height="168" width="168">

<param name="movie" value="gamestar.swf">

<param name="quality" value="high">

<param name="wmode" value="transparent">

<embed src="gamestar.swf" wmode="transparent" quality="high" pluginspage="http://www.macromedia.com/go/getflashplayer" type="application/x-shockwave-flash" height="168" width="168">

</object>

结果flash背景半透明失效了，ie和Chrome都正常。。。奇怪的是，同样html，在ubutnu下同样是firefox49里就显示正常....