Transparent in StyleSheet doesn't work on Linux

[Sampi]

I gave a Window some StyleSheet in order to have rounded corners using this block of code:
*{
background: transparent;
}
QWidget{
background-color:qlineargradient(spread:pad, x1:1, y1:0.323, x2:1, y2:1, stop:0 rgba(80, 80, 80, 255), stop:1 rgba(41, 41, 41, 255));
border: 2px solid rgb(153, 153, 153);
border-radius: 20px;
color:white;
}
the widget is appearing well but the window doesn't take the transparency I gave in order to get rid of pointy corners...
On windows this code worked

[mrjj]

Hi
Your windows manager might not support it.
What linux distro and manager are you using ?