Thank you for writing and please accept my apologies for the delayed reply.
In the WinForms technology only forms have Opacity property and the value of that property is inherited by all controls placed on that form.
If what you want to do is to make the back color transparent then you can just set the BackColor property of the RadPanel to Color.Transparent. You should note that in WinForms transparency actually means that the back color of the control is set to the color(s) of the parent control.
If this is not what you want I would kindly ask you to provide some more details on what are you trying to achieve.
I am looking forward to your reply.
All the best,
the Telerik team
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