I use wikitext editor. When I want to ping someone, I can copy his name form discussion above.
With this reply tool I don't see source. Problem is, when somebody have different username than appears in his signature e.g. [[User:John Walker|Johnnie Walker]], in that case user doesn't receive ping on his account.
It would be fine, if there is possibility to include ping template on the beginning with prefilled name of author of previous post. JAn Dudík (talk) 11:17, 7 August 2020 (UTC)