return, home and close app buttons unresponsive

[dfc2013]

I have a Z3 Dual, all of my screen is responding perfectly to touch however the return, home and close app button are all unresponsive and only work after several touches, i have reset the phone and still no lucky
luck. Has anyone else experienced this or know how to fix it?

[Qatrium]

Go to Settings -> About phone -> Diagnostics -> Test -> Touchscreen -> See if all screen parts are responsive.

[Christa1]

same problem for me, touchscreen ist working fine, diagonstics okay, but the 3 lower buttons are not working!