The `UCKeyTranslate` function was being used wrong. The `deadKeyState` param should use `kUCKeyTranslateNoDeadKeysMask` instead of `kUCKeyTranslateNoDeadKeysBit` (optionally could also use `(1 << kUCKeyTranslateNoDeadKeysBit`)). This commit also dispenses with accessing the keyAction, as this is not crucial for determining the key. Comments have also been added to better describe the code. Pull Request: https://projects.blender.org/blender/blender/pulls/109987