var w = new Window ('dialog', title, undefined, {closeButton: false}); 
w.alignChildren = 'right'; 
var tpanel = w.add ('tabbedpanel'); 
tpanel.alignChildren = ['fill', 'fill']; 
tpanel.size = [550,400]; 
var anleitung = tpanel.add ('tab', undefined, 'Anleitung'); 
var loadPanel = tpanel.add ('tab', undefined, 'Laden'); 
var placePanel = tpanel.add ('tab', undefined, 'Platzieren'); 
.... 

tpanel.selection = loadPanel; 

tpanel.onChange = function () 
{ 
$.writeln(tpanel.selection.text);     
    }