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]Related issues
is duplicated by
relates to
Attachments
Comments


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).

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.

Still in 20w12a

Still in 20w13b

Affects 20w14a

Affects 20w19a

Affects 20w20a

Affects 20w22a

Affects 1.16 Pre-release 2

Affects 1.16 Pre-release 3

Affects 1.16 Pre-release 4

Affects 1.16 Pre-release 5

in 1.16RC1

Affects 1.16.1

Affects 20w27a

Affects 20w28a

Related to MC-86455.

In 20w29a

In 20w30a

Affects 20w46a

In 1.16.4
In 20w51a

In 21w03a

In 21w10a

In 21w11a

In 21w13a

In 21w14a

In 21w16a

In 21w17a

Can confirm in 21w18a.

Can confirm in 21w19a.

Can confirm in 21w20a.

Can confirm in 1.17 Pre-release 1.

Can confirm in 1.17 Pre-release 2.

Can confirm in 1.17 Pre-release 3.

Can confirm in 1.17 and 1.17.1 Pre-release 1.
Giving ownership of this ticket to @unknown.

Still a bug in 1.19.2, haven't checked in later versions

Fixed in 24w38a.