The bug
When double clicking on an item in the creative survival inventory, it no longer collects stackable items into a stack.
How to reproduce
Get a full stack of any block
Split it in two separate stacks, both in the top 3 rows of your inventory
Double click one of the stacks
→ ❌ Notice it didn't combine into a full stack of 64
The bug in action: http://gfycat.com/ShowyPeskyAustraliancattledog
Notes
This only occurs when viewing only your inventory, not while you have a block inventory (e.g. chest) open
This only occurs when the item that is double-clicked is not in your hot bar, see http://gfycat.com/DecisiveAllClam
Linked issues
is duplicated by 7
MC-69893
Inventory Bug
Resolved
MC-86452
Double clicking item stacks to collect items from across the inventory doesn't work in creative survival inventory
Resolved
MC-95458
Double Click Item Stacking in Creative
Resolved
MC-111438
Unable to double click items in creative inventory to group
Resolved
MC-116970
Cannot triple click items to stack them in creative mode
Resolved
Comments 9
Confirmed for 15w44b. Plus the 'Some more information I noticed' info should be in bold/highlighted as it is an important part of how to reproduce this issue.
Confirm 1.9.4.
Only works porperly in hot bar but not in inventory!
https://gyazo.com/8a08a279a7eb5c3e01bbf7b25245133a
Confirmed.