navlistPanel example with tasetPanel - dataset not showing up

server.r

library(shiny)
shinyServer(function(input, output, session) {
  
  output$table1 <- renderTable({
    mtcars
  })
  
  output$summary1 <- renderText({
    summary(mtcars)
  })
  
  
})

ui.r

library(shiny)
library(datasets)

shinyUI(fluidPage(
  titlePanel("Demo navlist panel navigation layout in shiny"),
  navlistPanel(
    "Data", 
    tabPanel("About", h3("This is the first tab or page")),
    tabPanel("Data Table", tableOutput("table1"), h3("This is the first tab or page")),
    tabPanel("Data Summary", verbatimTextOutput("summary1")),
"Tabsets",
    tabPanel("Tabsets",
             tabsetPanel(tabPanel("Plot", plotOutput("plot")),
                         tabPanel("Summary", verbatimTextOutput("summary")),
                         tabPanel("Table", tableOutput("table")))
    ),
    "Plots",
    tabPanel("Scatter Plot",h3("Can have widgets and plots")),
    tabPanel("Histogram",sliderInput("bins", "bins", min=5, value=15, max=25),tableOutput("table"))

    )))