Requested feature
An undo button when you add a post to a set or pool.
Just in case you add something to the wrong set or pool.
Example: post #6268 added to set 'favorite SFW images' (Undo)
Why would it be useful?
Right now you have to manually go to the affected set or pool to remove posts. Which is a bit tedious.
What part(s) of the site page(s) are affected?
Sets and pools