Collapsible box not responding in my navbarPage Rshiny

[Koffi Frederic Sessie]

I'm working on a small R Shiny application, but I'm facing an issue where the boxes aren't collapsing when I click on them. I've tried various approaches without success. Could someone assist me in resolving this?

Additionally, I'd like to know how to customize the appearance of these boxes.

Here is a minimal example:

library(shinydashboard)
library(DT)
library(highcharter)
library(shinyjs)
library(shinythemes)  

# I using getSymbols to retrieve data
the_data <- getSymbols("AAPL", src = "yahoo", from = "2018-11-07", to = Sys.Date(), auto.assign = FALSE)
# The keep only the "Adjusted Close" as time serie
Prix_de_cloture <- Cl(the_data)

#My UI part
ui <- fluidPage(
  titlePanel(""),
  navbarPage(
    "Clusters de Volatilité",
    header = tagList(
      useShinydashboard()
    ),
    inverse = TRUE,
    theme = shinytheme("cerulean"),
    shinyjs::useShinyjs(),
    shinyjs::inlineCSS(
      ".main-sidebar { background-color: #f8f9fa; }"
    ),
    tabPanel("Analyses primaires",
             sidebarLayout(
               sidebarPanel(align = "center",
                            selectInput("ticker", "Choisir un Ticker :", c("AAPL", "MSFT", "GOOGL", "AMZN")),
                            dateRangeInput("date", strong("Choisir les dates"),
                                           start = "2020-01-06", end = (Sys.Date()-1))
               ),
               mainPanel(
                 fluidRow(
                   # DT Table
                   box(title = "Comparizon table",
                       status = "primary",
                       solidHeader = TRUE,
                       collapsible = TRUE,
                       DTOutput("Comparizontable"),
                       width = 12,
                       height = 'auto'),
                   br(), br(),

                   # Highchart
                   box(title = "Closing price chart",
                       status = "primary",
                       solidHeader = TRUE,
                       collapsible = TRUE,
                       highchartOutput("closing_price"),
                       width = 12,
                       height = 'auto')
                 )
               )
             )
    )
  ))

server <- function(input, output) {
  output$Comparizontable <- renderDataTable({
    info.mat <- structure(c(9.342, 9.354, 9.342, 9.347, 9.344, 9.36, 9.344, 9.35,
                            9.349, 9.369, 9.349, 9.356, 9.37, 9.39, 9.37, 9.378, 9.345, 9.365,
                            9.345, 9.353), dim = 4:5, dimnames = list(c("Akaike", "Bayes",
                                                                        "Shibata", "Hannan-Quinn"), c("Arch(1,1)", "GARCH(1,1)", "TGARCH(1,1)",
                                                                                                      "EGARCH(1,1)", "GJR-GARCH(1,1)")))
    datatable(info.mat, escape = FALSE)
  })

  output$closing_price <- renderHighchart({
    # Trying to plot the graph
    hchart(the_data)
  })
}

# Run the application
shinyApp(ui, server)