I don't know if this is bug or if it was changed deliverately. In previous versions (5.3 and before?) you could right click and operator (like normalize) and click on "Enable Operator". The operator remained connected but it was ignored when the process was executed. Now the behavior is different: when you click "Enable Operator" the operator greys out but the ports also disconnect. In order to "enable it" you have to connect manually the ports.