Need some help with GUIs

[OiRodgar]

I need some help with GS2 again

After I scripted a little shop, I wanted to script a shop with a GUI.
I made a GUI but somehow the text in GuiMLTextCtrl won't change when I select something in GuiTextListCtrl.

Here is my script

PHP Code:

//#CLIENTSIDE
function onPlayertouchsme() {

  new GuiWindowCtrl("Shop_Window4") {
    profile = GuiBlueWindowProfile;
    clientrelative = true;
    clientextent = "544,447";
    visible = true;
    canmove = true;
    canresize = false;
    canmaximize = false;
    closequery = false;
    destroyonhide = true;
    text = "Willkommen im Waffenshop";
    x = 29;
    y = 115;

    new GuiScrollCtrl("Shop_TextList1_Scroll") {
      profile = GuiBlueScrollProfile;
      height = 426;
      hscrollbar = "alwaysOff";
      vscrollbar = "dynamic";
      width = 120;
      x = 9;
      y = 15;

      new GuiTextListCtrl("Shop_TextList1") {
        profile = GuiBlueTextListProfile;
        height = 426;
        horizsizing = "width";
        width = 99;

        clearrows();
        addrow(0,"Bombe");
        addrow(1,"Bogen");
        addrow(2,"Nukeshot");
        addrow(3,"Fire Ball");
      }
    }
    new GuiScrollCtrl("Shop_MultiLine1_Scroll") {
      profile = GuiBlueScrollProfile;
      height = 426;
      hscrollbar = "dynamic";
      vscrollbar = "dynamic";
      width = 403;
      x = 138;
      y = 14;

      new GuiMLTextCtrl("Shop_MultiLine1") {
        profile = GuiBlueMLTextProfile;
        height = 16;
        horizsizing = "width";
        text = "<center><h1>Willkommen im Waffenshop!</h1><br> Hier erhalten sie eine Vielzahl an Mitteln um Ihre Gegner auszulöschen</center>";
        width = 378;
      }
    }
    new GuiButtonCtrl("Shop_Button1") {
      profile = GuiBlueButtonProfile;
      text = "Kaufen";
      width = 80;
      x = 286;
      y = 380;
    }
  }
}

function Shop_TextList1.onSelect(0,Bombe,1) {
Shop_MultiLine1.setText("Info Info Info");
}

function Shop_Button1.onAction() {
  // Button "Kaufen" has been pressed
}