I'm not sure. I know it's possible to have furnaces that are always lit, but chests that are always open, I'm not sure about. I'll have to look into that.
I believe it's just a case of sending a packet to players that are within viewing distance of the chest. However I'm not sure wich packet it is.
I think it is this one. https://github.com/PocketMine/Pocke...c/pocketmine/inventory/ChestInventory.php#L47
PHP: $pk = new BlockEventPacket();$pk->x = $x;$pk->y = $y;$pk->z = $z;$pk->case1 = 1;$pk->case2 = 2;$level->addChunkPacket($x >> 4, $z >> 4, $pk);[PHP]i think you should make it always when chunk loads