How to set the curved radius to left edge of the form in WinForms RibbonControlAdv?
Customizing the top left edge
The TopLeftRadius property gets or sets the curved radius of the top left edge of the form.
C#
this.TopLeftRadius = 8;
VB
Me.TopLeftRadius = 8
Reference link: https://help.syncfusion.com/windowsforms/ribbon/ribbon-form#customization