The bug
When editing (but not when reading) a book, you can select all buttons at once by pressing Tab
repeatedly.
How to reproduce
Get a book and quill
Press
Tab
a few times
→ ❌ You will be able to select multiple buttons at once, and at one point even all buttons visible in the GUI.
Example
Here is an example in video:
[media]Linked issues
relates to 2
Attachments
Comments 21
This issue is blocked by MC-262268.
Can confirm this bug in 1.14 Pre-Release 2