I experienced that. I was able to change mine but it took a while to see it. It kind of slow things down after the upgrade. I was juggling around the themes before I saw it. I keep on getting different slider background and slider. Phone kept freezing when done is tapped.
I was using the reflect theme but having problems with the new virtual keyboard. It doesn't show the up arrow key and back arrow key but it still work withouth the image (just get blank space). I went back to the original theme since the reflect theme have problems with the new virtual keyboard.
Did you change it on the desktop screen? I'm having problem when I used the desktop tool screen. The phone freezes after I tap done. I have to switch off and on the phone. Sometimes it okay but most times it just freezes when I tap done. i don't know the fix for the freezing episodes.