AppLayout Drawer Tab isnt showing after there is at least 2 Tabs

Hi,
I have problem with showing tabs in my Applayout, when i have only one Tab then my View isn`t showing if i have 2 Tabs and setSelectedTab for second tab then my view for both Tabs is showing correctly, i can select 1st Tab and view is showing. This is code where my tabs views are showing correctly:

		Tabs tabs = new Tabs();

		Tab mainTab = new Tab(div);			
		mainTab.setLabel("Main Tab")
		
		Tab mainTab2 = new Tab(div);
		mainTab2.setLabel("Main Tab2");

		tabs.add(mainTab);	
		tabsToPages.put(mainTab, div);
	        
		tabs.add(mainTab2);	
		tabsToPages.put(mainTab2, div);
**	    tabs.setSelectedIndex(1);
**		
		tabs.addSelectedChangeListener(event -> {
	        final Tab selectedTab = event.getSelectedTab();
	        final Component component = tabsToPages.get(selectedTab);
	        tabs.setSelectedTab(selectedTab);
	        setContent(component);
	      });

And this code isnt showing my View for first tab but when i change to second tab then again to first the it work correctly(drawing my view)

		Tabs tabs = new Tabs();

		Tab mainTab = new Tab(div);			
		mainTab.setLabel("Main Tab")
		
		Tab mainTab2 = new Tab(div);
		mainTab2.setLabel("Main Tab2");

		tabs.add(mainTab);	
		tabsToPages.put(mainTab, div);
	        
		tabs.add(mainTab2);	
		tabsToPages.put(mainTab2, div);
**	    tabs.setSelectedIndex(0);**
		
		tabs.addSelectedChangeListener(event -> {
	        final Tab selectedTab = event.getSelectedTab();
	        final Component component = tabsToPages.get(selectedTab);
	        tabs.setSelectedTab(selectedTab);
	        setContent(component);
	      });