The most common reason for teachers' computers not displaying correctly, eg cutting off the bottom row, not allowing browsing for files, etc, is that the teacher is using a browser which is not supported. Most commonly, the culprit is Internet Explorer. Internet Explorer is not a supported browser in Accelerus Light.
Alternatively, if a supported browser is being used and there are still issues with the display, try refreshing the screen by pressing Shift + F5. Clearing the cache may also resolve some issues. Should the problem persist after this, an Accelerus report administrator may need to contact the Accelerus Light support desk.