Looks like you changed the declarative style previously used to keep options up to date to an imperative style where you have to manually manage updating it. Was this because certain important variables were not observables and thus `computed` wasn't working properly? If you haven't already, I think it's worth looking into whether you can preserve the declarative style by making sure all variables that could change are ko observables. If that turns out to be too complex (requiring tons of changes throughout the code) then we can fall back on this.