Companies are migrating their software systems. The migration process contemplates many steps, UI migration is one of them. To validate the UI migration, most existing approaches rely on visual structure (DOM) comparison. However, in previous work, we experimented such validation and reported that it is not sufficient to ensure a result that is equivalent or even identical to the visual structure of the interface to be migrated. Indeed, two similar DOM may be rendered completely differently. So, we decide to focus on the layout migration validation. We propose a first visual comparison approach for migrated layout validation and experiment it on an industrial case. Hence, from this first experiment and already existing studies on image comparison field, we highlight challenges for layout comparison. For each challenge, we propose possible solutions, and we detail the three main features we need to create a good layout validation approach.