Incorrect copy-paste behavior in the header

[Kuuuzya]

If you copy a word in the title and try to paste it there, it will be pasted 3 times! And then 4 times and more. In addition, in 100% of cases, it is not the word that is copied, but the ENTIRE title. It is impossible to edit the title using basic functions (copy, cut, paste); you always have to write it manually or edit it character by character.

1. Create a new post
2. Write any title
3. Select 1 word or several letters, press Ctrl+C
4. Go to the end of the title (or any other place) with the cursor and press Ctrl+V.