GUI.DragWindow() dont work in C# (Unity 4.2), Java works?

Hey Everybody.

I build a simplyfied example of the problem. I am using Unity 4.2 on Windows7 x64.

If I program a samplecode in JS with a dragable window it works fine:

 var windowRect : Rect = Rect (20, 20, 165, 50);
 
 function OnGUI () {
 
     windowRect = GUI.Window (100, windowRect, DoMyWindow, "TESTWINDOW JavaScript - movable");
 
 }
 
 function DoMyWindow (windowID : int) {
 
     GUI.DragWindow (Rect (0, 0, 300, 50));
 
 }

If I build a similar code for C# the window is NOT dragable. I read the documentation for it and searched the ANSWERS and forums about that without success... whats the problem?

 using UnityEngine;
 using System.Collections;
 
 public class testwindow : MonoBehaviour {
     
     Rect windowRect = new Rect(10, 100, 200, 100);
     
     void OnGUI() {
         GUI.Window(101, windowRect, windowDo, "TESTWINDOW c# - movable");    
     }
     
     void windowDo(int windowID) {
         
         // dont work????
         GUI.DragWindow(new Rect(0, 0, 200, 100));    
     }
 }