1) The power off/reboot/screenshot menu is popping up when pressing power btn two times (first short, second long) even at the locked phone. This is common android problem, but if the company (Sony) respects their users security - it must fix this **** in the firmware.
2) The screenlock has no exact setting. The only thing remained is putting device in sleep mode during predefined idle time. But this feature is just ignored when developer option "keep screen on during charging" is enabled - it is just huge security flaw/hole.
My previous phone Xperia Z3 behaved more securely - it just locks the screen in any such dev option mode set. You just had the locked screen always on.
2) The screenlock has no exact setting. The only thing remained is putting device in sleep mode during predefined idle time. But this feature is just ignored when developer option "keep screen on during charging" is enabled - it is just huge security flaw/hole.
My previous phone Xperia Z3 behaved more securely - it just locks the screen in any such dev option mode set. You just had the locked screen always on.