codex crashes when using option key/backspace with arrows to jump between words #4006
Closed as duplicate of#3991
Description
What version of Codex is running?
0.39
Which model were you using?
gpt-5
What platform is your computer?
Darwin 24.6.0 arm64 arm
What steps can reproduce the bug?
When I have a long chat with Codex (and the context is quite filled), suddenly using OPTION + arrow key or backspace can crash the app.
The application panicked (crashed).
Message: assertion failed: self.is_char_boundary(n)
Location: tui/src/bottom_pane/textarea.rs:97t 1.29M tokens used 55% context left
Backtrace omitted. Run with RUST_BACKTRACE=1 environment variable to display it.
Run with RUST_BACKTRACE=full to include source snippets.
The behavior is replicable in iTerm / Terminal / Zed / VSCode
What is the expected behavior?
I should be able to use Option key whenever I want and I shouldn't crash the app.
What do you see instead?
No response
Additional information
No response