The bug
Sometimes, the Survival inventory in Creative is not cleared when shift-clicking onto the X button.
To reproduce
Load a full 9-slot quick-toolbar with X+[number]
Pick-block a block or item (so that one item from the quickbar gets moved to the inventory)
Loading that or any other quickbar with X+[number]
Open the Survival Inventory inside the Creative Inventory
Shift-click the red "Destroy Item" button
→ ❌ The items moved into the inventory out of the quickbar by pick-blocking have not been deleted
Videos
[media]Linked issues
is duplicated by 6
MC-156883
Shift-clicking the X in the Survival inventory in Creative mode does not destroy all of the items.
Resolved
MC-174436
Some items cannot be cleared from inventory after shift-clicking on the "Destroy Items" button in creative mode
Resolved
MC-182082
Creative inventory clear function not working correctly
Resolved
MC-184258
"Delete All" button in Creative menu works inconsistently when pickblocking and swithing hotbars.
Resolved
MC-190563
Creative inventory not fully clearing when shift-clicking the "destroy item" icon.
Resolved
relates to 2
Attachments
Comments 38
After some further experimentation, I found that the items are not getting deleted because they are ghost items (for some reason–which is why this bug report exists). /data get entity @p Inventory shows that the item is not saved in your inventory, reloading the world causes it to disappear, grabbing the item in survival mode causes it to disappear, etc.
I can confirm this also works in 1.14.4.
Based on the video you linked and my own experimentation, here's a procedure to replicate the bug:
Fill the hotbar as much as desired (can be left empty, but filling it with as many as 9 items makes step 2 quicker).
Pick-block anything from the world that is not already in your toolbar. Continue doing this until there is at least 10 different items in your inventory (i.e. a full hotbar, and at least 1 item not in your hotbar).
Load any toolbar.
Open to the "Survival Inventory" tab.
Shift-click the "Destroy Item" button.
And, like you said, any blocks which had been pick-blocked will not be deleted.
Some various, potentially helpful notes:
Loading a toolbar before doing the pick-blocking is not necessary, but it definitely makes the bug reproduction process faster.
For step 3, you can use any toolbar.
You can repeat steps 1, 2, and 3 as many times as you want, in any order (so long as the minimal requirements for the bug are met).