Sigma Shulkers

Allows you to open shulker boxes without placing them.

Right click a shulker box inside the inventory screen (E) to open it. You must be in Creative Mode to do this. Also, since this mod is entirely client side, you may need to open your inventory and move the changed items around to make sure they are synced with the server after opening the shulker box and moving any items in/out of your inventory.