[How to set Panel CornerRadius]

Hi, I create a Panel with:
 

auto panel = CreatePanel(0,0,400,400,ui->root);

panel->SetColor(1,1,1,1);
panel->SetRadius(16);

That works for me with buttons and other widgets, however on Panels it doesn't seem to work.

Is it not done that way? Is it possible to do it? Am I doing something wrong?

Thank u ?