Optimal control of partial differential equations (PDEs) is by now, after more than 50 years of ever increasing scientific interest, a well established discipline in mathematics with many interfaces to science and engineering. During the development of this area, the complexity of the systems to be controlled has also increased significantly, so that today fluid-structure interactions, magneto-hydromechanical, or electromagnetical as well as chemical and civil engineering problems can be dealt with. However, the numerical realization of optimal controls based on optimality conditions,...