Creation and transformation of visual specifications is driven by modeler’s design decisions. After a design decision has been made, the modeler needs to adjust the specification to maintain its correctness. The number of adjustments might make the design process tedious for large specifications. We are interested in techniques that will reduce the modeler’s obligation to control specification correctness. Every single transformation of the visual specification can be captured by the notion of refinement used in formal methods. In this work we present the technique that supports a stepwise refinement of visual specifications based on calculations. We use refinement calculus as a logic for reasoning about refinement correctness. When a design decision is made by the modeler, the necessary adjustments are calculated based on rules of refinement propagation. Refinement propagation can automate the specification adjustment and enforce its correctness.