If you've rooted your Android phone or tablet, no doubt you've used SuperSU. It's a great app used to control the permissions of other apps, and a must-have if you want to walk the dark side.
The advent of multi-user support for Android tablets breaks a lot of things, including the way root permissions is granted when more than one user is on the same device. Tonight's update of SuperSU is the first step to fixing that. Chainfire, the developer, says it's not nearly complete but it's a start. This update allows the primary owner to control root access, and block access for secondary users. It a nice safe way to proceed until everything gets sorted.
If you're using SuperSU, hit the Google Play link above to update.