Using the BBC editor.
I wrote up this post: https://www.simplemachines.org/community/index.php?topic=582847.msg4129491#msg4129491
...half way through writing it up, I had selected an image BUT NOT UPLOADED IT. I completed writing up the post. After I was done I clicked POST and the system reminded me that there was an attachment that was not uploaded. I uploaded it and then attempted to use the editor to move my cursor to where I wanted to insert it.
The editor was dead. I could do nothing. No selecting... nothing. I did click INSERT and it put the insert tag in the wrong place... between the paragraphs. I attempted to move the tag... but the editor was still dead. I could do nothing. I saved. It displayed with the image in the wrong place (as expected). I then MODIFIED the post and it did work as normal and I could move the tag (which I did). I then immediately came here to report the issue.
Moving to Bug Reports.
Fixed in 2.1.3