filter leaflet map per year using crosstalk

Question

I would like to filter my leaflet map per year using crosstalk with the filter_select function like this example. So when we select a year it should change the data of the leaflet map. Unfortunately nothing happens. Here is some reproducible code:

library(tidyverse)
library(gapminder)
library(leaflet)
library(countrycode)
library(sf)
library(rnaturalearth)
library(crosstalk)

df <- gapminder %>% #filter(year == 2007) %>% 
  mutate(iso_a3 = countrycode(country, "country.name", "iso3c"), 
         gdpPercap = round(gdpPercap, 0), 
         lifeExp = round(lifeExp, 0))

world <- ne_countries(type = "countries",  returnclass = 'sf') %>% 
  left_join(., df, by = "iso_a3") %>% 
  filter(!is.na(country)) %>% 
  select("country", "continent" = "continent.y", "year", "lifeExp", "pop", "gdpPercap", "geometry") %>% 
  as('Spatial')

world_NA <- ne_countries(type = "countries",  returnclass = 'sf')

sd <-  SharedData$new(world)
sd_df <- SharedData$new(world@data, group = sd$groupName())

pal <- colorFactor(c("#1f77b4", "#ff7f0e", "#2ca02c", "#d62728", "#9467bd"), domain = c("Africa", "Americas", "Asia", "Europe", "Oceania"), ordered = FALSE)

bscols(
  list(
    filter_select("filter_year", "Choose the year:", sd_df, ~year),
    filter_slider("lifeExp", "Life expectancy (years):", sd_df, ~lifeExp),
    filter_slider("gdpPercap", "Income per person ($):", sd_df, ~gdpPercap)
  ),
  leaflet(sd) %>% 
    addProviderTiles("CartoDB.Positron") %>% 
    addPolygons(data = world_NA, color = "#969696", weight = 1, fillColor = "#808080") %>% 
    addPolygons(color = "#969696", weight = 2, fillColor = ~pal(continent), fillOpacity = 0.8)
)

Output:

As you can see when we change the year and some variable with the filter nothing happens. I think it has something to do with the sharedData but I don't know exactly.