The problem of composing a system using well-behaved components is discussed. Specifically, necessary conditions for preserving the behaviour in a system context are analysed in this paper. Such conditions are defined as Context-Dependent Constraints (CDC). A non-formal approach is taken based on common system integration errors. It is suggested that the identification and verification of CDCs should be part of any development method based on component verification. The CDCs can also serve as an aid for designing reliable and maintainable systems, where the goal of the design process is to reduce the number of CDCs.