Thanks for reporting these issues. I don't know if they have been around since the updates we made a couple of weeks ago or whether they are a consequence of fixes we've put in place since then.
However, I wasn't previously aware of them. I've not logged them with our developers and hopefully they should be able to get them fixed soon.
I should add that the 'save changes' button higher up the page does work. It's only the one at the bottom of the page for which nothing happen when you click on it.But even using that button won't close the thread - to do that at the moment you'll need to go in to thread and use the option in the 'Thread Tools' drop down.