Index Selectable Filters and probe/stim

I have an application where changing between 4 sets of IIR coefficients would be advantageous and found the

index selectable filter. I loaded my 4 sets of coefficients and they save fine (there are threads about problems with that)

but I am unable to see any change in the probe window when I change the 28.0 DC block driving the index pin to anything other than 0.

I have tried hitting the stim button again. Nothing seems to change it. It always seems to use the index 0 filter coefficients.

I haven't tried this in hardware yet (testing some concepts) but I am curious if this is a problem with the filter block or

does it simply not work in simulation?