Yes, Android KitKat introduced this very annoying feature.
http://www.androidcentral.com/kitkat-sdcard-changes
That's one reason that I bought a 32 Gbyte Z2 rather than the 16 Gbyte. Some apps (e.g. File Commander) that come installed on the tablet can access the external SD card. But most that can be downloaded from the Play Store can't, and certainly very few seem to be able to have their installation moved to the external SD card. So the whole user-accessible memory sysem is considerably less useful and less convenient than early versions of Android.
Not Sony's fault. And I hear that they are slowly introducing work arounds on their phones to try and help users out. But another black mark for Google, IMHO.
The SD card is on the tablet remains good for bulk storge of media files.
To overcome this issue completely, you can root your device, and install SDFix from the Play Store.
-chris
