intellij-plugin-v4: UI freeze after parse on SQL grammars with large inputs

I’m trying to profile my SQL grammar on a large input with diverse statements, which used to go fine in previous versions some years ago. I managed to consistently reproduce a UI freeze that seems to happen after parsing of the input is finished. Looking at the CPU load, there’s a ~15s multithreaded parser spike and then a single thread becomes pinned at 100% and UI freezes. Considering this and #381 it seems that the issue is with displaying parsing/profiling results. And it happens even when disabling every option on the left of the preview panel (auto-update, parse-tree etc).

Repro: Use example PostgreSQL grammar or my PostgreSQL grammar. Test root rule (sql rule in my grammar). Concat every example SQL into a single file, i used this command: find *.sql | xargs -I{} sh -c "cat {}; echo ''" > _concat.sql. Use the new, ~2.9MB file as ANTLR Preview input. Note UI freeze after a short delay (parse stage). UI doesn’t unfreeze for at least 10 minutes, process has to be killed.