Large image slow refresh transparency control

[Erakis]

Hi,

I need to put a very large image as background (1030px X 774px) on the
main window of my application. Also, on this window I need to add
transparent Usercontrol, Panel and Label.

Every time I need to refresh or replace a Usercontrol, the redraw is
doing very TOO slow and there some flickering... I try to activate the
double buffering but without success. Same refresh speed.

I try to realize the same application using MFC, the refresh was
really more fastest. I can say Perfect ! Why I cannot get similar
performance using .NET C# ? Beacause we don't have enough time to
create the project using MFC.

Here is a link to an exemple of my problem. http://70.54.205.43/Test.rar
Try to move another window over my application and minimize it after.
Check how it too slow to refresh transparent control

Thanks for you help