Looked through the default config and my user.json, but nothing seems to stand out as being likely to be the issue. I have the Comments plugin installed and the HTML lexer is working fine for syntax, auto-complete is OK, just can not comment out a line or a block.
Anyone else seen this, and/or could someone point me in the direction of where I have this wrong? It's not a game changer but it is surely annoying

Many thanks
Tony