Share your experience!
I have the same problem on my Xperia Z1 after lollipop update.
I worked around the issue by:
1. Reboot into safe mode
2. Turn on Switch Access accessibility service
3. Assign Volume up/down keys to Next and Select in Switch Access settings
4. Reboot into normal mode (and fix all your widgets that disappear)
5. Go into the accessibility settings that you want to use, and use volume keys to select the OK button and select.
I'm not sue how to raise a bug against the lollipop build, but if anyone knows, then please raise a bug/issue.