When having a block or item in hand you can't interact with blocks eg cant open chests, furnaces, crafting tables, can't sleep in beds. when holding a block it places block rather than interacting with the block (chest, furnace, bed, crafting table)
Linked issues
Comments 4
Are you holding shift when you try to interact with blocks? Btw, you dont know if it will be in 1.6, so dont add that version.
can't reproduce