Java applet'涵盖'facebook对话框

When deploying an applet, (almost?) every facebook popup dialog is covered by the applet. The webpage is written in PHP, and the applet is deployed with applet tag. Results are the same with JNLP starter.

The error is present in the following browsers:

  • Chrome - version 32.0.1700.107
  • Opera - version 16.0.1196.62
  • Opera - version 19.0.1326.59
  • Internet Explorer - version 8.0.7600.16385 It only seems to work well with Firefox (tested with version 27.0)

Screenshot:

enter image description here

On the screenshot the applet covers a chat window and the messages window. Is there any way to send the applet to the "background", so other panels become fully visible?

Thanks in advance