It is easily possible to lose annotations when exiting SpeedGrader. this is because sometimes it takes a while to load the annotations made into the file submitted for the assignment, but SpeedGrader does not let the user know this.
To prevent this problem, there should be a lockout/warning message while SpeedGrader is saving the annotations.
"Loading Annotations to File. Click Here if you wish to abort the load ___ "
This would notify the user and at the same time lock-out returning to Navigation (Grades). In case of a hang-up situation there should be an out - i.e. the ~'do you wish to abort the load' option.
J. Schaffert; Chemistry professor, Foothill College, Los Altos Hills, CA