Visual Editor doesn't behave correctly when editing and adding text with combining diacritics.
For example insert the text "ɛ́" (ɛ is character U+025B, combining acute is U+0301).
When the cursor is behind "ɛ́":
- pushing the left arrow doesn't move the cursor
- adding text like "ɛ́abcdef" is fine but:
- pushing backspace gives "ɛ́abcda" instead of expected "ɛ́abcde"
- pushing return ives "ɛ́abcde\na"
Some languages require combining diacritics, many keyboard layouts allow their input or user can insert them by copying and pasting from somewhere else.