Good Night, I have finished now the RibbonRoundButton, this is like the WM player, Of2007 and VSTA round buttons, and includes fading between colors. I designed with .net 2.0, I think it's a eye candy and it works fine.
I'll publish it in codeproject with the RibbonForm and the Updated RibbonMenuButton with the InfoForm and ContextMenuStrip.
It was difficult to add a shadow under the circle region but at the end I think it finished well.
Another matters with that is the stranges halos that has inside and over, in a few days you will have all the code.