I cant control the sliders in the options menu with the index controllers (they work on my vive wands still)
Just a quick question, do you hold the knuckles controller with other fingers? If so, could you try relaxing your fingers and just pressing trigger (which might be not comfortable)?
When I finish the feature I am working on now, I have a task to revisit recent grab support for UI (it was meant to be used as a swipe but it doesn't make much sense, as joystick is a much better fit for scrolling).