I had previously added guards in FXNode against spurious bounds change notifications so that we didn't send those spurious changes on to FX. In some cases this is what you want, in others it is counterproductive because to implement this I had to recompute bounds. This meant lots of recomputed bounds when not strictly necessary. Rather, we should remove these guards and instead fix the real problems of spurious changes at their source. Other bugs in this bug group address these other issues.