Show Tab menuItem after it has been hidden in shiny dashboard - shinyjs

Question

I have a dashboard with several (planned - only two shown here) tabs. After the app has been started, the user should see only the first tab "settings" to load data. After the data have been loaded the other tabs should appear.
I managed to hide the tab "Plot" with hidden() but I have problems to have it appear properly:
whereas the selectInput item appears correctly on the sidebar, the Plot "menuItem" is not shown. I would like to see the Tab "Plot" below settings, so that the user can switch between tabs as soon as the dataset has been chosen. In principle it should look like without the hidden function. I'd be grateful for any help on this.
Here is a reproducible example:
library(shiny)
library(shinydashboard)
library(shinyjs)
ui <- dashboardPage(
dashboardHeader(title = "plot datasets"),
dashboardSidebar(
useShinyjs(),
sidebarMenu(id = "menu", style = "position: Scroll; overflow: visible",
menuItem("Setttings ", tabName = "settings",icon = icon("wrench")),
hidden(
menuItem("Plot",tabName = "Plot",icon = icon("envira"))),
conditionalPanel(condition = "input.menu == 'Plot'",
tags$hr(),
selectInput(inputId = "Variables", label = "Variables", choices = NULL)
)
)
),
dashboardBody(
tabItems(
tabItem(tabName = "settings",
fluidRow(style = "background-color:#D3D3D3;",
column(12,h2("Test mtcars"),h3("Please adjust some settings:")),
),
fluidRow(
column(6,
tags$br(),
selectInput(inputId = "set", label = "Which dataset do you want to plot?",
choices = c("","mtcars","iris"), selected = "")
),
)
),
tabItem(tabName = "Plot",
plotOutput("plot1")
)
)
)
)
server <- function(input, output, session){
data <- reactive({
if(input$set == ""){
NULL
}else{
name <- as.character(input$set)
get(name)
}
})
observe({
choice <- colnames(data())
updateSelectInput(session, "Variables", "Variables", choices = sort(choice))
})
observeEvent(nrow(data())>1,{
req(input$set)
show(selector = '[data-value="Plot"]')
})
output$plot1<- renderPlot({
p <- plot(data()[,2:3])
p
})
}
shinyApp(ui, server)