OpenTK.NativeWindow.OnFocusedChanged C# (CSharp) Method

        protected virtual void OnFocusedChanged(EventArgs e)
        {
            if (!Focused)
            {
                // Release cursor when losing focus, to ensure
                // IDEs continue working as expected.
                previous_cursor_visible = CursorVisible;
                CursorVisible = true;
            }
            else if (!previous_cursor_visible)
            {
                // Make cursor invisible when focus is regained
                // if cursor was invisible on previous focus loss.
                previous_cursor_visible = true;
                CursorVisible = false;
            }
            FocusedChanged(this, e);
        }