This paper addresses issues of using computer technology to support in-classroom teaching and learning regarding one of the most frequent problems in such scenarios: the students' attention. First, it presents the distraction and focus of attention problems that arise while using computer technology with off-the-shelf software for supporting different activities which take place in usual lectures. Examples of these activities are presentations of learning material, discussion, individual and collaborative problem solving, and difficulties of switching from one to another. A solution to this problem is an integrated approach with a particular implementation under the notion of "CiC". The implemented system attempts to reduce the number of interactions needed to switch from one activity to another as well as to reduce the cognitive load for both teacher and students. The usage of both this system and standard software are compared and research results are presented. Results show the CiC is useful to solve the problem. (Contains 3 figures and 3 tables.)