If the window is maximized then you cannot rely on window.Left or window.Top at all since they may be the coordinates before it was maximized. But you can do this in all cases:
var screen = System.Windows.Forms.Screen.FromHandle(
new System.Windows.Interop.WindowInteropHelper(window).Handle);
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…