This paper is a pre-print of: Oskar van Rest, Guido Wachsmuth, Jim Steel, Jörn Guy Süß, Eelco Visser. Robust Real-Time Synchronization between Textual and Graphical Editors. In Keith Duddy, Gerti Kappel, editors, Theory and Practice of Model Transformations, Sixth International Conference, ICMT 2013, Budapest, Hungary, June 18-19, 2013. Proceedings. Lecture Notes in Computer Science, Springer Verlag 2013. In modern Integrated Development Environments (IDEs), textual editors are interactive and can handle intermediate, incomplete, or otherwise erroneous texts while still providing editor services such as syntax highlighting, error marking, outline views, and hover help. In this paper, we present an approach for the robust synchronization of interactive textual and graphical editors. The approach recovers from errors during parsing and text-to-model synchronization, preserves textual and graphical layout in the presence of erroneous texts and models, and provides synchronized editor services such as selection sharing and navigation between editors. It was implemented for synchronizing textual editors generated by the Spoofax language workbench and graphical editors generated by the Graphical Modeling Framework.