This report falls within the research area of separation of concern (SOC). We present an in-depth discussion of the concepts concerns, separation, self containment, and invasiveness. These conceptsare commonly used in relation to SOC, and when talking about the readability andcomprehensibility of software artifacts. The term separation describes a relationship between software artifacts, in specific, we can have syntactical, semantical, and physical separation. The term self containment is used to measure the comprehensibility of software artifacts. Finally, invasiveness is used to describe the consequences of a modification to a software artifact. This can be consequences to the syntax or semantics of the artifact, or the labor involved in performing the modification. This report also contains a description of the tool gbnav, a development and source code navigation tool aimed at the programming language gbeta. This tool affects how the SOC related concepts relate to programs at the source code level. The tool is build on top of the emacs text editor and the graph-tool daVinci. The primary aim of the tool is to improve comprehensibility of programs written in gbeta.