To quote from a PM discussion that I had with SUPER in March 2023:
" Whether the attachment dialog is present is determined by which forum the thread is in.
If it's in the General Forum (like Mr No's "All Engines Go NEWS" thread), then attachments are allowed.
If it's in pretty much any other Forum, they are not allowed. "
I'm not sure that this is still strictly true, but it is certainly the case that the attachment dialog is not uniformly available from one forum to another. It may also depend on individual user permissions. I'm sure it will be sorted out soon though.
" Whether the attachment dialog is present is determined by which forum the thread is in.
If it's in the General Forum (like Mr No's "All Engines Go NEWS" thread), then attachments are allowed.
If it's in pretty much any other Forum, they are not allowed. "
I'm not sure that this is still strictly true, but it is certainly the case that the attachment dialog is not uniformly available from one forum to another. It may also depend on individual user permissions. I'm sure it will be sorted out soon though.