I’ve been working on integrating bs4Dash components within a Shiny module and have encountered an issue where the tabs created with bs4TabItems inside a bs4DashPage are not displaying correctly.

Goal: To create a bs4DashPage that contains multiple tabs (bs4TabItems), each defined inside a Shiny module.

Issue: The tabs are not rendering any content when the module is used within bs4DashBody.
The module function reservationAppUI is intended to output a series of tabs, but when these are integrated within the main bs4DashPage using bs4DashBody, the content appears empty or does not display as expected.

library(shiny)
library(bs4Dash)
library(DT)

# Define the UI for the module
dataAppUI <- function(id) {
  ns <- NS(id)
  
  # Use bs4TabItems directly as this is going to be part of a bs4DashPage
  bs4TabItems(
    bs4TabItem(tabName = ns("dataTableTab"),
               fluidRow(
                 DTOutput(ns("dataDisplayTable"))
               )
    ),
    bs4TabItem(tabName = ns("addDataTab"),
               fluidRow(
                 box(title = "Data Entry Form", status = "primary", solidHeader = TRUE, width = 12,
                     "Input form elements for data entry go here."
                 )
               )
    ),
    bs4TabItem(tabName = ns("adjustmentsTab"),
               fluidRow(
                 box(title = "Adjust Settings", status = "primary", solidHeader = TRUE, width = 12,
                     "Adjustable settings for the application go here."
                 )
               )
    ),
    bs4TabItem(tabName = ns("settingsTab"),
               fluidRow(
                 box(title = "Configuration Settings", status = "primary", solidHeader = TRUE, width = 12,
                     "Configuration options for application settings go here."
                 )
               )
    ),
    bs4TabItem(tabName = ns("userManagementTab"),
               fluidRow(
                 box(title = "User Management", status = "primary", solidHeader = TRUE, width = 12,
                     "Manage user credentials and access levels."
                 )
               )
    )
  )
}

# Define the server logic for the module
dataApp <- function(input, output, session) {
  output$dataDisplayTable <- renderDT({
    datatable(
      data.frame(
        Description = c("Item Description"),
        Quantities = c("1,2", "3,4"),
        `10:00` = c(0, 100),
        `11:00` = c(0, 123),
        `12:00` = c(0, 0),
        `13:00` = c(0, 0),
        check.names = FALSE
      ),
      options = list(pageLength = 5, autoWidth = TRUE)
    )
  })
}

# Main application code using bs4DashPage
ui <- bs4DashPage(
  title = "Generic Data App",
  header = bs4DashNavbar(
    title = "Generic Data App",
    sidebarIcon = icon("bars"),
    skin = "light"
  ),
  sidebar = bs4DashSidebar(
    skin = "light",
    status = "primary",
    bs4SidebarMenu(
      id = "sidebarMenu",
      bs4SidebarMenuItem("Data Table", tabName = "dataTableTab", icon = icon("table")),
      bs4SidebarMenuItem("Add Data", tabName = "addDataTab", icon = icon("plus")),
      bs4SidebarMenuItem("Adjustments", tabName = "adjustmentsTab", icon = icon("sliders")),
      bs4SidebarMenuItem("Settings", tabName = "settingsTab", icon = icon("cogs")),
      bs4SidebarMenuItem("User Management", tabName = "userManagementTab", icon = icon("users"))
    )
  ),
  body = bs4DashBody(
    dataAppUI("mainApp")
  )
)

server <- function(input, output, session) {
  callModule(dataApp, "mainApp")
}

shinyApp(ui, server)