How to create an rhandsontable with fixed headers?

Question

Can someone advise me on how to fix column headers in an rhandsontable? Below there is a sample script I have written, but it does not work. It seems that I could not use hot_cols() in a proper way. I need help to amend this script or get an alternative one for this task.

library(shiny)
library(shinydashboard)
library(rhandsontable)

# Define the UI
ui <- dashboardPage(
  dashboardHeader(title = "Fixed Column Headers"),
  dashboardSidebar(),
  dashboardBody(
    fluidRow(
      box(
        title = "Table with Fixed Column Headers",
        width = 12,
        solidHeader = TRUE,
        status = "primary",
        rHandsontableOutput("table")
      )
    )
  )
)

# Define the server logic
server <- function(input, output) {
  output$table <- renderRHandsontable({
    rhandsontable(data = iris, readOnly = TRUE, width = "100%", height = "400px") %>%
      hot_cols(colHeaderClassName = "fixed-header")
  })
}

# Run the application
shinyApp(ui, server)