RS flip flop has 3 modes of operation "Trigger": None-normal asynchronous mode of operation, "Clock" - the state of the RS inputs are read by a positive voltage drop at the input ">". "InEnable" - the state of the RS inputs are read when there is a high voltage level and at the input "In". When the voltage level at the input "In" is low, the RS inputs do not work. When running the simulation, the outputs can have both outputs in high level or in low level, i.e. the state of the output is undefined. These options can be set in the RS-latch properties. There you can also disable the inverting of the RS inputs.