Virtual navigation bar below the screen Xperia models always do some people feel like by natural screen lost a corner rather pointless. It looks like Sony is trying to overcome it by creating a navigation bar completely transparent on-screen display superimposed on the image.
There have only been Xperia UL (ZR) is Sony test this unique feature on the menu of the application, when the functions are the black navigation bar is displayed normally. Hopefully the international models will soon be updated similar features and will be unlocked at all functions.