[Firefox] Caret is stuck at the end of a link when pressing left arrow key quickly

[Reinmar]

Is this a bug report or feature request? (choose one)

🐞 Bug report

💻 Version of CKEditor

latest master

📋 Steps to reproduce

1. Open http://localhost:8125/ckeditor5-core/tests/manual/article.html
2. Put selection at the end of the link, press right arrow key and type few letters.
3. Start moving selection over the right link boundary using arrow keys. Press them quickly and multiple times each (e.g. 5x left, 5x right ).

✅ Expected result

The caret should move as expected – staying at the link boundary for two subsequent arrow key presses.

❎ Actual result

It sometimes happen that the selection won't move to the left – it's stuck at the right link boundary.

📃 Other details that might be useful

Make sure to press the arrow keys quite quickly. Don't press and hold.

Most likely, it's some timing issue. It's caused by ckeditor/ckeditor5-link#179 so, most likely, by the fact that we re-render the selection and put it in some odd space between two inline elements.

[Reinmar]

I decided to not merge ckeditor/ckeditor5-link#179, so this issue doesn't occur.