Marco Brambilla 0001, Romina Eramo, Alfonso Pierantonio, Gianni Rosa, Eric Umuhoza. Enhancing Flexibility in User Interaction Modeling by Adding Design Uncertainty to IFML. In Loli Burgueño, Jonathan Corley, Nelly Bencomo, Peter J. Clarke, Philippe Collet, Michalis Famelis, Sudipto Ghosh, Martin Gogolla, Joel Greenyer, Esther Guerra, Sahar Kokaly, Alfonso Pierantonio, Julia Rubin, Davide Di Ruscio, editors, Proceedings of MODELS 2017 Satellite Event: Workshops (ModComp, ME, EXE, COMMitMDE, MRT, MULTI, GEMOC, MoDeVVa, MDETools, FlexMDE, MDEbug), Posters, Doctoral Symposium, Educator Symposium, ACM Student Research Competition, and Tools and Demonstrations co-located with ACM/IEEE 20th International Conference on Model Driven Engineering Languages and Systems (MODELS 2017), Austin, TX, USA, September, 17, 2017. Volume 2019 of CEUR Workshop Proceedings, pages 435-440, CEUR-WS.org, 2017. [doi]