rounded corners on Collapsible Panel

Is it possible to have rounded corners on a collapsible panel?

I just tried to do so and the corners are not rounded and I lose a border off one of my panels. If I remove the rounded corners the border is fine again.

Hi,

May be you can wrap the collapsible in a Panel, and have RoundedCorner on it.

Please try it, and feel free to let me know if there is any problem.