When the user deletes the node D1 of this decision analysis network (DAN) and then clicks on the button S (Straregy), then there is a NullPointerException: "D1 not found in network DAN-unordered-three-decs-no-chance.pgmx".
The problem appears even after saving the network. However, if the user saves the network, closes it and reopen it, then the problem doesn't appear.
I think the problem is because the InferenceAlgorithm object managed by the GUI should be created again when the network has been modified and before invoking again the method getOptimalStrategy().
I attach a network to reproduce the bug.