We use Java and we ran into this issue as well.
LiveWindow doesn't seem to work at all, but all of the actuators and sensors seem to be there in one LiveWindow block if you enable the robot in
test mode. If you have a lot of sensors and actuators, you may have to put the SmartDashboard in Editable mode and drag the LiveWindow block up to see the other values.
For looking at sensor values, it might be much easier just to do a SmartDashboard.putNumber(key, number) (java) in your teleop command and enable the robot in
teleop mode.
Good Luck
