With the default theme it doesn't work still.
However when I try to uncheck extensions nothing happens and when I change page and come back in they are again checked.
No way to uncheck them, in addition I have a bug when I pass the mouse over control here is what I have:
Please submit a ticket with admin CP access details and we will look into this. The fact that there are problems in the control panel may point to files not being uploaded completely or other server software interfering.
If using CloudFlare, disable Rocket <exp>Loader. Otherwise, have you ran a file health check to make sure all files are there?
yourdomain.com/admin.php?tools/file-check