I am having the same issue, I can't stand having to hit the active button after scrolling to a preset. I bought the Barn3 OX9, which works great, but you still have to hit the damn active switch, and in the middle of a song, this can make or brake a transition.
I think you misunderstood what he wrote above. You assign a particular aux switch to a pedal function. This works the same regardless if it's a Barn3 OX9, an FSX3 or any other aux switch. There is a pedal function called 'Increment preset' which leaves the preset in a pending state, but there is also a pedal function called 'Increment and load preset' which immediately loads the preset. If this is the behavior you want you just have to choose this as the pedal function. In H9 Control you find these mappings by clicking on the Pedal button in the bottom menubar and going to Aux Switch Mapping. You can change these settings on the H9 as well. Please check the H9 manual for instructions on how to do that.
