Ext.onReady(function(){
    var learn;
		var button = Ext.get('show-learn');
    showBtn5 = Ext.get('show-learn');
     Ext.get('show-learn').on('click', function(){  
        if(!learn){
            learn = new Ext.Window({
                applyTo     : 'learn-win',
                layout      : 'fit',
                width       : 440,
                height      : 240,
                x: 240,
                y: 240,
                closeAction :'hide',
                plain       : true,
                items       : new Ext.TabPanel({
                    applyTo        : 'learn-tab',
                    autoTabs       : true,
                    activeTab      : 0,
                    deferredRender : false,
                    border         : false
                }),

                buttons: [{
                    text     : 'Close',
                    handler  : function(){
                        learn.hide();
                    }
                }]
            });
        }
       learn.show(button);
    });
});