Thank you for raising this. There has recently been a fix for the problem you describe, so it seems we have missed a way that this can happen.

To help investigate what needs to be fixed, do you remember any details about where the comment was being posted? For example, do you know which post or comment thread you were trying to post a comment in? If not, it would still be helpful to know whether it was a question, answer, or comment thread.

Yes, I have commented this question. The comment was long, and afaik it had also some formatting markups. Note I am using a firefox on Linux with a lot extensions, although javascript instability happens rarely by me, it is a possible problem source. I might try to reproduce it. But I think it is not a client side problem. I have also clicked "start a new comment thread". Nothing warned me that I should not.

trichoplax‭ Wow! I have got the "participate everywhere" ability, yet the problem still exists.

Thank you for the additional information. If I've understood correctly, you were incorrectly shown the option to:

• Add a comment to an existing comment thread under a question by another user.
• Start a new comment thread under a question by another user.

Neither option should be displayed to you until you have gained the ability to post comments there, so we will look into this. I agree it is unlikely to be a client side problem. The intention is that the site should work even with JavaScript disabled.

I'm sorry that this wasted the time you spent writing your comment. Thank you for helping narrow down the bug.

I didn't see your message from 5 minutes ago until after pressing send.

At first that sounds like a different bug, but it's because you have "Participate Everywhere" here on Meta (where you can comment). On Software Development you only have "Participate", which restricts where you can comment. See the difference between your profile pages on the two communities:

• Profile on Meta
• Profile on Software Development

Hopefully this explains the difference in where you can comment between the two communities (although letting you try to comment where you can't is still a bug we need to look into).

However, having said this, it now occurs to me that the name "Participate Everywhere" is misleading. It means "everywhere on that community", but "everywhere" might naturally be assumed to mean all communities. I'll recommend renaming that to be unambiguous.

Ok my please. Another fun: now I could comment here: https://physics.codidact.com/posts/288288 Note that I registered physics codidact only after I have got the "participate everywhere" ability.

That's due to a difference in the way different communities treat abilities for new users. The natural state of a community is that a new user only gets "Participate" at first, and earns "Participate Everywhere" later. However, since most communities are still small, new users are given "Participate Everywhere" immediately. Only a few larger communities like Software Development make new users wait for "Participate Everywhere". Meta and Physics both give new users this ability immediately.

I've raised Ambiguous ability name to see if someone can think of a clearer name.

Okay. Now, "Participate Everywhere" means that I can write comments on all the sites, or that I can write comments on the all the posts, but only on the site I have got it? I am a total newbie to this part of the system. My first thought was that "Everywhere" means here all the sites, and not only all the posts (of the current site).

I agree that is confusing, so I raised a new Meta post to change it to a less confusing name.

To clarify: "Participate Everywhere" only means everywhere on that one community. So you currently have Participate Everywhere on Meta and Physics, but not on Software Development.