Naturally, If block is moved by piston some can able to move, some will drop instead. Those blocks that will drop when moved, cannot cancel pistonActivate event.
Like for example a shulker box, if shulker box is moved it'll drop instead. Using beforeEvent.pistonActivate to cancel piston activation will not work and will still drop, it can't cancel the event. How should I make to these kinds of blocks be immovable or wouldn't drop if moved?