Rong position using Rect.Contains and GUI.Button

Hi every one, I started a mini project on Unity 3D and encounter this weird situation, when I use the Contains function and the GUI.Button to get the mouse over a button this happens:

The Rect to use with the Contains function is set using this coordinates and size (0, 0, 128, 64), when I test the function the Rect is on the bottom left and the GUI.Button is on the top left, here is the code.

var rect : Rect = Rect(0, 0, 128, 64);

function OnGUI() {
if (rect.Contains(Input.mousePosition)) {
print("Its over me");
} else {
print("Its out");

GUI.Button(rect, "Button");


So please any one can explain me why is this difference or it's a kind of bug in the program, also when I use the GUI.matrix = Matrix4x4.TRS() to scale the GUI about the screen size, the GUI.Button conserve the position but the rect move away from the button, for your attention thank you very much.

Input.mousePosition uses screen space coordinates, which are inverted from GUI coordinates. Don't use anything from Input in OnGUI, use Event.current instead, like Event.current.mousePosition. Then you get data appropriate for OnGUI.