RTC: [Interface] List updates clear out the list items in the block inspector sidebar

[maxschmeling]

Editing a list in a collaborative session causes the list items to be cleared from the block inspector sidebar for other connected clients. See the video for an example.

CleanShot.2026-02-18.at.08.34.45.mp4

[chriszarate]

@maxschmeling Is this the right video? It looks like expected behavior.

[maxschmeling]

@maxschmeling Is this the right video? It looks like expected behavior.

Watch the inspector controls sidebar on the right side

[chriszarate]

Ah, thanks, somehow got locked onto the List View

[alecgeatches]

Here's a slightly longer reproduction since it took me a few tries to catch it:

Screen.Recording.2026-02-27.at.1.55.30.PM.mov

1. Enable RTC and open a post in two separate tabs.
2. On one tab, open the "Document Overview" and click on the List block.
3. Note the list items viewable on the right sidebar.
4. On the another tab, add a new list item to the same list.
5. On the first tab, the right sidebar of list items will go blank.

[alecgeatches]

I have a draft PR up to fix this at #76025.