Black screen in my C# project

[Jay Hao]

Hello all
I am a new guy in here. Recently I met a problem when I did my C# project.
This project is that: use the VLC control in the VS 2005 to look the programs on the local area network.The programs are sent by the server using the UDP protocol. I put 3 VLC controls on the form. Using "addtarget()" method to play. When the project is running, all of the VLC windows display the programs which are sent from the server. But sometimes, after I use "Alt + Tab" to switch another program in OS, minimize the form or open a dialog box on the form, one of the VLC winows will becom black. I am sure that the program is playing on the black screen. It is just no display. I was puzzled how to solve it. Plese help me.
Thank you very much!
P.S. The VLC' edition whcin I use is 0.8.5.

[Jean-Baptiste Kempf]

Deactivate Overlay in VLC preferences.