Type a Vietnamese word

   Press space after the word

   Immediately press backspace to delete the space

   Then type a punctuation mark, such as ,, ., (, ), ;, etc

   The entire word just typed is deleted immediately after pressing the punctuation key.

   This issue does not happen in other browsers like Chrome or Edge.

   It only occurs when using the Windows built-in Vietnamese IME (not 3rd-party input tools like EVKey or Unikey).

   The bug seems related to how Firefox handles IME input, especially when mixing backspace and punctuation.

   It is very disruptive when typing Vietnamese naturally, especially in form fields, textareas, or comments.

I'm experiencing a consistent issue when typing Vietnamese using the built-in Windows Vietnamese keyboard (IME) in Firefox. Steps to reproduce: Type a Vietnamese word Press space after the word Immediately press backspace to delete the space Then type a punctuation mark, such as ,, ., (, ), ;, etc The entire word just typed is deleted immediately after pressing the punctuation key. Notes: This issue does not happen in other browsers like Chrome or Edge. It only occurs when using the Windows built-in Vietnamese IME (not 3rd-party input tools like EVKey or Unikey). The bug seems related to how Firefox handles IME input, especially when mixing backspace and punctuation. It is very disruptive when typing Vietnamese naturally, especially in form fields, textareas, or comments. Please look into this issue or let me know if there’s a workaround. It's been a consistent obstacle when typing Vietnamese and I don't want to use another tool just to type Vietnamese in Firefox, thank you.