GUI freezes on get_initial_params()
Because get_initial_params() is called on the GUI thread at the moment, the GUI freezes whenever this function takes a long time. This could happen e.g. if the optimization problem fetches the current machine state.
Ideally, we query get_initial_params() on the background thread. This means we can't initialize x0 in the SingleOptimizableJob constructor. So it might be None.