Put the summary of the bug you're having here

What I expected to happen was...:
The items in my offhand slot would stack when i broke the item that was in my offhand slot

What actually happened was...:
I had to manually drag the item into the offhand slot

Steps to Reproduce:
1. Put any item into your offhand slot
2. Then go mine the thing that can craft it or you mine it and it gives you the item in your offhand slot
3. Pick it up and you will get the same bug that i found