In this paper, we describe the enhancement of an intelligent tutoring system for teaching details of program-element scope in the C++ programming language. We expanded the range of learned content, introduced hints with informative descriptions, and provided detailed feedback on errors during premature completion of a learning problem. In addition to scope and visibility, the new tutor can also teach the concept of object lifetime and data flow direction. We conducted an experiment to evaluate the effects of the tutor improvements on the learning process. The results showed that while the overall level of learning gains increased, the gains in some of the topics remained the same and for the most complex topic, they decreased because the students were distracted by the new material. It shows that when expanding intelligent tutors, the teachers should also consider expanding the time spent with the tutor. It was also shown that the students who actively used hints learned significantly more than the students who ignored that feature.