RibbonModule.RoundRectShade
From Jeremie Leroy - XOJO Controls Wiki
Method
RibbonModule.RoundRectShade ( p As Picture, X As Double, Y As Double, Width As Double, Height As Double, Arc As Double, ShadeLength As Double, CenterColor As Color = &c0, ExteriorColor As Color = &cFFFFFF ) As Picture
