New Note option not visible when canvas area is full

[karthick-murugan]

Description

When attempting to add a new note to a block, the New Note interface does not appear if the canvas area is already filled with existing notes.

This issue seems related to limited available space in the canvas — once some existing notes are resolved or removed, the New Note interface becomes visible again and works as expected.

Step-by-step reproduction instructions

1. Open a block and start adding multiple notes until the canvas area is fully occupied.
2. Try to add another note using the Add Note option from the toolbar.
3. Notice that the New Note interface does not appear.
4. Resolve or delete one or more existing notes to free up space.
5. Attempt to add a new note again — the New Note interface now appears correctly.

Screenshots, screen recording, code snippet

REC-20251029173346.mp4

Environment info

• Wordpress 6.8.3
• Gutenberg 21.9.0

Please confirm that you have searched existing issues in the repo.

• Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

• Yes

Please confirm which theme type you used for testing.

• Block
• Classic
• Hybrid (e.g. classic with theme.json)
• Not sure

[Mamaduka]

I think this is technically the same problem as #72440.

cc @adamsilverstein

[adamsilverstein]

I think this is technically the same problem as #72440.

Yes, this is essentially the same issue. We have two potential solutions so far (that could be combined):

#72547 - makes threads scrollable
#72454 - ensures bottom of active floating note is never cut off at bottom

@karthick-murugan thanks for the bug report, I'm going to close as a duplicate of #72440. Feel free to reopen if I missed something.

[Mamaduka]

Actually, this might be a slightly different problem with a stale selectedThread value, which I overlooked in the original PR. I've a solution and will push it shortly.