That is so weird, since it changes to a green glowing cursor when i use it to scroll around the map
Perhaps westwood intended there to be a TS mouse cursor, but didn't finish it. I understand that EA pushed the dead line quite a lot.
I also encountered some lag in the mission "Destroy prototype facility" most of the lag occured when the AI used underground vehicles, but some of it seemed random (Meaning: i did not see any direct cause)
For some reason i was also unable to construct a tech lab in this mission, but i think it might just be part of the mission.