Original sentence: Additionally, because there is no revision locking feature, if two graders update the same grades simultaneously through the Web interface, the work of one of them will not be saved.Blackboard has been criticized for it's use of [intellectual property] laws against competitors.Entering student grades is time consuming.The Blackboard Academic Suite has been criticized for the design of its Gradebook system
Edited sentence: Also mounting to the problems, the system takes up to a minute during this process, requiring the grader to spend hours in front of the computer to update a few simple grades.Despite all these serious problems, Blackboard remains popular partly because of lack of competition in the educational-software industry.It takes a very long time to enter the individual student grades and the interface is extremely inefficient, such as providing an unnecessary "Override" feature that locks a current grade, as well as linking the grader back to original gradebook home page after every time an individual grade is updated.The Blackboard Academic Suite has been highly criticized for having a very poorly designed Gradebook system.The worst defect of the Gradebook is that there is no locking feature and if two graders update the grades simultaneously through the Web interface, the work of one of them will be completely erased