Whenever Someone Places A Block(Torch, Hoppers ETC.) On Another Functioning Block(Crafting Table,Chest, Dispenser,Dropper ETC.) While Crouching, The Block Doesn't Place And The Functioning Block Opens Or Starts.

Examples:-

1) If Placing A Hopper On A Chest, It Doesn't Places And The Chest Opens.

2) If Placing A Torch On A Crafting Table, It Doesn't Places And The Crafting Table Opens.