When clicking on the "delete post" button (little X in the corner of each post) on viewtopic.php and selecting to open in a new tab, only the last one opened will be deleted. For example
"Delete post a" in a new tab
"Delete post b" in a new tab
"Delete post c" in a new tab
press "ok" for tab b - "sorry you can only delete your own posts"
press "ok" for tab c - post deleted (because it was the last one clicked)
press "ok" for tab a - "sorry you can only delete your own posts"
This was all tested as the board administrator within firefox 220.127.116.11.
I don't know why this is but the board administrator should never be told that the reason that the delete did not work was because it was not their post, as they have the authority to delete all of them.
I assume that this is because of some global variable that is getting overwritten each time the delete post button is pressed.