Existing block comments are included in the undo stack when loading a project, lose their content on redo

[towerofnix]

Expected Behavior

The undo/redo stack for a given workspace only ever contains specific actions the user takes. Also, "redo" always fully restores the changes undone by "undo".

Actual Behavior

Loading a project with block comments considers loading each of those comments an "action" for undo/redo purposes. Pressing undo removes the comment. Then, pressing redo doesn't restore the contents of the comment, leading to data loss.

Steps to Reproduce

1. Create a new, blank project
2. Drag out any block
3. Right click the block and choose "add comment"
4. Type something in the comment
5. Save and reload the project (F5)
6. Press ctrl/cmd+Z or right click -> undo
   • Note the comment disappears
7. Press shift+ctrl/cmd+Z or right click -> redo
   • Note the comment reappears attached to the block but has no contents

Operating System and Browser

N/A (macOS 13.4, Chromium 112; first reported by a Scratcher on unknown browser/device)

[towerofnix]

See also:

• @apple502j's list of comment-related issues: Comment position and "Save Now" issues scratch-gui#5948 (comment)
• My previous case of an undo/redo issue with comments: Undoing removing a block which had a comment attached does not restore the comment #1936

[towerofnix]

Whoops, duplicate of #1973!