[TIMOB-15283] iOS: SplitWindow does not respond to focus events

   var tabGroup = Ti.UI.createTabGroup();
   
   var tabWindow1 = Ti.UI.createWindow({
       backgroundColor: 'red'
   });
   
   var tabWindow2 = Ti.UI.createWindow({
       backgroundColor: 'pink'
   });
   
   tabWindow1.addEventListener('focus', function(e) {
       Ti.API.info('tabWindow1 FOCUS');
   });
   
   tabWindow1.addEventListener('blur', function(e) {
       Ti.API.info('tabWindow1 BLUR');
   });
   
   tabWindow2.addEventListener('focus', function(e) {
       Ti.API.info('tabWindow2 FOCUS');
   });
   
   tabWindow2.addEventListener('blur', function(e) {
       Ti.API.info('tabWindow2 BLUR');
   });
   
   var tab1 = Ti.UI.createTab({
       tintColor: 'black',
       title: 'Tab 1',
       window: tabWindow1
   });
   
   var tab2 = Ti.UI.createTab({
       tintColor: 'black',
       title: 'Tab 2',
       window: tabWindow2
   });
   
   tabGroup.addTab(tab1);
   tabGroup.addTab(tab2);
   
   
   var detailWindow = Ti.UI.createWindow({
       backgroundColor: 'gray'
   });
   
   var navWindow = Ti.UI.iOS.createNavigationWindow({
       window: detailWindow
   })
   
   var splitWindow = Ti.UI.iPad.createSplitWindow({
       detailView: navWindow,
       masterView: tabGroup,
   }); 
    
   splitWindow.addEventListener('visible',function(e){
       if (e.view == 'detail') {
           e.button.title = "Popover";
           detailWindow.leftNavButton = e.button;
       }
       else if (e.view == 'master') {
           detailWindow.leftNavButton = null;
       }
   })
   
   splitWindow.open();