OpenTK4 https://opentk.net/learn/chapter1/2-hello-triangle.html?tabs=onload-opentk4%2Conrender-opentk4%2Cresize-opentk4#some-new-functions What in sample is ```csharp protected override void OnFramebufferResize(ResizeEventArgs e) { base.OnFramebufferResize(e); GL.Viewport(0, 0, e.Width, e.Height); } ``` but the parameter in source is ```csharp protected virtual void OnFramebufferResize(FramebufferResizeEventArgs e) { Action<FramebufferResizeEventArgs> framebufferResize = this.FramebufferResize; if (framebufferResize == null) return; framebufferResize(e); } ```