it is currently bugged out.
some users are complaining that the save button is grey and they cant click it.
this is in fact a bug and it is being worked on.
in the mean time, you can hit CTRL+S on your keyboard, this has been tested to work in Google Chrome
also be sure to clear your cache when the hotfix releases so you can get it as soon as you can without issues. if
you need assistance with clearing your cache i have posted another post about it here