Hantek MSO5102D setting the system clock

[Ringtone]

Hi all.
I've recently received my Hantek MSO5102D.
All is working as expected, and generaly i'm happy.
But (and theres always a but).
How do you set the system time.
Mine is showing China time. so following the on screen instructions:-
utility menu page 2,
F4 (time),
"use the knob V0 to sellect the option"---all good so far hour selected,
"pressV0 and the option turns red"---- still good hour is now red,
"Activate the option. turn V0 to set value"---??? how? no matter what I press, turn or twiddle the hour wont change. either nothing happens or the box turns black and the highlighted option changes.
Is this a firmware bug? am i doing somthing wrong or am I just going mad?