private static void HandleMouseButtonDown(NMouseButton mouseButton, Win32Window window, Win32MessageType messageType, uint wParam, uint lParam) { int x = (short)(lParam & 0xFFFF); int y = (short)((lParam >> 16) & 0xFFFF); Win32API.SetCapture(window.WindowHandle); window.StartupInfo.OnMouseButtonDown(mouseButton, new Point(x, y), GetModifierKey()); }