HiHat Open/Closed Sounds and 'mute groups'

[paulf707]

I know there are many comments about the 2Box HiHats and how good (or not) they are.
Mostly, I'm happy with mine so far, but I've found some odd behaviour and I want to check if this is 'normal'.
I don't think it's a calibration issue (but please correct me if I'm wrong).
I'm using Groove_15_HiHat off the default 'Live' kit on the D5.

I can get 3 or 4 different samples by moving the pedal (closed, 1/4 open, 1/2 open, fully open etc)
But as far as I can tell, the only thing that 'mutes' an open HiHat sample is the pedal closed action (i.e. HH pedal fully depressed). I can play a fully open sample, and then close the pedal slightly and play 1/2 open samples (while the fully open sample continues to 'ring'). If I'm careful with my foot I can actually get the pedal down enough to play closed HiHat samples while the open HiHat sample is still playing. This leads to a fairly unnatural sound.
On older electronic drums (and drum machines), open and closed hihat sounds would be in a 'mute group' so that one automatically stops the other.
It seems that the D5 is relying purely on the pedal closed action to stop the other samples?

Can anyone confirm if this is 'normal', something that can be adjusted by settings somewhere, or perhaps a problem I've caused by modifying my hihat pad??

Thanks