Using reactiveValues to updateSelectInput in RShiny

Question

I've been following the instructions here for creating an editable dataTable in R Shiny. Now I want to update the user's choices for another input, but the values are not updating in pickerInput(), as they correctly do in the renderPrint() function.

Can anyone enlighten me on the best way to use updateSelectInput() when trying to get objects stored within reactiveValues()? Thanks in advance.

library(DT)
iris$Species = as.character(iris$Species)

shiny::shinyApp(
  ui <- fluidPage(
    DTOutput('x1'),
    pickerInput(
      inputId = "x2",
      label = "",
      choices =  unique(iris$Species)
    ),
    verbatimTextOutput("print")
  ),

server <- function(input, output, session){
  x = reactiveValues(df = NULL)
  
  observe({
    x$df = iris
  })
  
  output$x1 = renderDT(
    x$df,
    rownames = F,
    editable = T)
  
  proxy = dataTableProxy('x1')
  
  observeEvent(input$x1_cell_edit, {
    info = input$x1_cell_edit
    str(info)
    i = info$row
    j = info$col + 1
    v = info$value
    x$df[i, j] <- isolate(DT::coerceValue(v, x$df[i, j]))
    updateSelectInput(session, "x2", choices = unique(x$df$Species)) #NOT BREAKING, BUT NOT WORKING
  })
  
  output$print <- renderPrint({
    unique(x$df$Species)
  })
}
)```