A rollback can remove or change shapes the UI still refers to.
- The selection drops shapes that are gone and the color picker that
edited them closes.
- The undo history is cut at the reverted action; it stays when no
entry holds a reverted change. Undo and redo commits carry real undo
changes and the history index they moved from, so a reverted Ctrl+Z
puts the change and the index back.
- An open path edition whose shape the rollback changed closes without
saving the editor's stale copy. The v2 text editor loads the reverted
text again; the WASM editor already showed it.
- The Alt measurements look the hovered shape up in the current data.
- Plugin setters, resize() and rotate() on a removed shape throw
"Shape not found", whatever the plugin's throwValidationErrors flag.