Forking from a reply failed with "This checkpoint changed after it was
created" whenever a tool call started before that reply and finished
after it, the shape of background Bash, Monitor, Task and Codex
terminals. The projection keeps one row per tool call from its start to
its latest update, so the row spans the reply, and the fork refused any
copied row that spans the checkpoint.
Copy such a tool call into the fork marked running: its state at the
checkpoint can't be read back. Plugin cards that span the checkpoint
stay out, and a cursor from another epoch or a reply that is gone is
still refused.
Okan YILDIRIM
6e2fee462f