Missing controls in RhinoMac's Mono runtime

My plugin fails to load on Rhino for Mac, due to being unable to resolve RadioButtonand TreeView. However, I believe thw two types should be in Mono, as documented here and here.

Indeed I cannot find them by typeof(System.Windows.Forms.Button).Assembly.GetTypes(). Does it mean Rhino’s Mono runtime isn’t up-to-date, or is it caused by something else?

I understand it’s recommended to move everything onto Eto but I am still looking for a simple workaround.