GUI.Window not updating.

I'm trying to display up to date information in a drag-able GUI.Window using GUI.Label. Unfortunately, the window draw func is only called about 3 times according to the debug scripts. How do I get the information to update every frame, or at the very least when the window is brought into focus or when the information changes? I'm essentially writing a character sheet for an RPG.

 @script RequireComponent(CharacterManager)
 
 var charMgr:CharacterManager;
 
 charMgr = gameObject.GetComponent(CharacterManager);
 
 var windowRect: Rect = Rect(25,175,250,175);
 
 function Awake(){
     useGUILayout = true;
 }
 
 function OnGUI() {
     windowRect = GUILayout.Window(0,windowRect,WindowFunction,"Character Sheet");
     
 }
 
 function WindowFunction(windowID:int){
     var statnames:String[];
     statnames = ["STR", "DEX", "CON", "INT", "WIS", "CHA"];
     Debug.Log("called");
     for (var i:int = 0; i < 6; i++){ 
         var ability:int;
         ability = charMgr.GetModifiedAttribute(i);
         var modifier:int;
         modifier = (ability-10)/2;
         GUILayout.BeginArea(Rect(0,25*i+25,250,25));
         GUILayout.BeginHorizontal();
         GUI.Label(Rect(0,0,30,25), statnames[i]);
         GUI.Box(Rect(100,0,30,25), String.Format("{0}", ability));
         GUI.Box(Rect(200,0,30,25), String.Format("{0}", modifier));
         GUILayout.EndHorizontal();
         GUILayout.EndArea();
     }
     GUI.DragWindow (Rect (0,0, 10000, 20));
 }

Any help would be greatly appreciated.