fyi: for chatboxes that may take CJK inputs, you MUST use "shift+enter to send" pattern. There is a reason why most multinational chat/LLM app providers always do that instead of simple enter to send even for single-line chatboxes; because plain enter to send breaks input for CJK users.
Specifically, Input Method Editors needed for CJK inputs(esp. for C and J), to convert ambiguous semi-readable forms into proper readable text, use enter to finalize after candidates were iterated with spacebar. While IME engines don't interchange between different languages, I believe basically all of them roughly follow this pattern.
Unless you specifically wants to exclude CJK users, you have to either detect presence of IME and work with it so that enter do nothing to the app unless conditions are met. Switching to shift+enter works too.
1: https://github.com/anthropics/claude-code/issues/8405
2: https://www.youtube.com/watch?v=mY6cg7w2eQU