It looks like the GRC convenience blocks for the filter tap generation don't have working callbacks -- although, from the YAML it looks like they should work. There might be a bug in there.
The actual filter generation callbacks work -- if you replace "lp_taps" in the low-pass filter with "firdes.low_pass(1, samp_rate, cutoff_high, transition, firdes.WIN_HANN), for instance, then changing the parameters with a QT GUI Range slider will work just fine. It's just the convenience blocks which don't work.
Nick