Previous work has found that (a) when software is developed collaboratively, concurrent accesses to related pieces of code are made, and (b) when these accesses are coordinated asynchronously through a version control system, they result in increased defects because of conflicting concurrent changes. Previous findings also show that distance collaboration aggravates software-development problems and radical colocation reduces them. These results motivate a semi-synchronous distributed computer supported model that allows programmers creating code asynchronously to synchronously collaborate with each other to detect and resolve potentially conflicting tasks before they have completed the tasks. We describe, illustrate, and evaluate a new model designed to meet these requirements. Our results show that the model can catch conflicts at editing time that would be expensive to manage at later times.