I specifically need help with updating plugins to 2021 that have ViewParts that do not use WPF Controls.
Previously, it was possible in a class extended from an AbstractViewPartController, to return a System.Windows.Forms.Control as the return value of the GetContentControl() method. Now, the return value has to be an IUIControl. Is there a way to return a Control that is both a System.Windows.Forms.Control and a IUIControl and so that the AbstractViewPartController will have access to the elements of the control? Or does the 2021 version of ViewParts only work with WPF Controls?