OS: macOS 11.2.3 Version: https://github.com/JetBrains/JWM/commit/56449f9f4b6c84334ee4c768cf6d4cf487660b1a Steps to reproduce: 1. `./script/run.py` 2. Create multiple windows by `cmd+n` 3. Close some windows by `cmd-w` [hs_err_pid11437.log](https://github.com/JetBrains/JWM/files/7000542/hs_err_pid11437.log)