Q: What does the lock symbol mean in the gradebook? 

A: The lock symbol appears when a teacher has overwritten an automatically generated value in the system.

This is the lock symbol:


For example if a student completes an assessment the grade automatically appears in the gradebook. If a teacher then decides that they want to add two more percentage points to the score for good behavior they can type in a new value. At that point a lock would appear to indicate that a manual override has been performed on that score.

If the teacher then chooses to revert to the original score they can do so, and at that point the lock icon would disappear, indicating that the score is now automatically generated again.