Sorry that Camera Raw UI is blank and not showing any of the tools.
Which version of Camera Raw are you using? Are you working with raw images?
We have seen similar issues when users have the Google NIK plugins installed. If you have them installed, you may want to disable or temporarily uninstall them to confirm whether that is the cause of this issue.
A work around is to press K key twice or press the F twice to switch the Camera Raw Filter out/into full screen mode.