Flex Facebook App iframe z-index/transparancy problem

I'm developping a Facebook Application in Flex, the application renders in facebook, but when I click the notifications tab, it appears behind the iframe, as you can see in the开发者_C百科 image below.

Does anyone have an idea what the problem might be?

http://i.stack.imgur.com/0lBjC.png

I've found the solution to the problem. In the html-template I added an attribute

atributes.wmode = "opaque";