Based on Linkify Plus. Turn plain text URLs into links.
Interesting... for some reason, LPP tried to linkify the URL in the title. LPP should only work on <body> element.
It seems that the <title> tag is inside the <body> tag:
You have to report this bug to ru-board's maintainer.
Strange bug
I don't know why, but this userscript hangs on forum.ru-board.com in Firefox. And, only if the TitleURL add-on is installed.
For example, register, go to Test subforum, post test comment to test topic - https://forum.ru-board.com/topic.cgi?forum=2&topic=2753&start=1020#lt
then try editing the comment. The browser becomes extremely unresponsive (it's difficult to bring up a menu or even close a tab)
Without TitleURL or without Linkify Plus Plus all works correctly.