The Eclipse Graphical Modeling (GMF) Framework provides the major approach for implementing visual languages on top of the Eclipse platform. GMF relies on a family of modeling languages to describe different aspects of the visual language and its implementation in an editor. GMF uses a model-driven approach to map the different GMF models to Java code. The framework, as it stands, provides very little support for evolution. In particular, there is no support for propagating changes from say the domain model (i.e., the abstract syntax of the visual language) to other models. We analyze the resulting co-evolution challenge, and we provide a transformation-based solution, say GMF model adapters, that serve the propagation of abstract-syntax changes based on the interpretation of difference models.