Nested Tabsets in Shiny?

Question

How can I create nested tabs in RShiny like the image below?

Where "Sales Performance" is the parent tab and "Open Quotes - LW" is the sub tab that rolls up under the "Sales Performance Tab"

I have a reproducible example using the iris dataset

library(shiny)
library(DT)

ui <- fluidPage(
  titlePanel("Tabsets"),
  sidebarLayout(
    sidebarPanel(
      textInput('search', "Search"),
    ),
    mainPanel(
      tabsetPanel(id = "tabsetPanelID",
                  type = "tabs",
                  tabPanel("Tab1", DTOutput('DT1')),
                  tabPanel("Tab2", DTOutput('DT2')),
                  tabPanel("Tab3", DTOutput('DT3'))
      )
    )
  )
)

server <- function(input, output, session) {
  output$DT1 = renderDT(iris)
  DTProxy1 <- dataTableProxy("DT1")
  
  output$DT2 = renderDT(iris)
  DTProxy2 <- dataTableProxy("DT2")
  
  output$DT3 = renderDT(iris)
  DTProxy3 <- dataTableProxy("DT3")
  
  observeEvent(c(input$search, input$tabsetPanelID), {
    updateSearch(DTProxy1, keywords = list(global = input$search, columns = NULL))
    updateSearch(DTProxy2, keywords = list(global = input$search, columns = NULL))
    updateSearch(DTProxy3, keywords = list(global = input$search, columns = NULL))
  })
}

shinyApp(ui, server)

What I currently have looks like the following:

Answer 1

You could add another tabsetPanel into each tabPanel of the main tabsetPanel.

   mainPanel(tabsetPanel(
      id = "tabsetPanelID",
      type = "tabs",
      tabPanel("Tab1", tabsetPanel(
        tabPanel("SubPanelA1"), tabPanel("SubPanelA2")
      )),
      tabPanel("Tab2", tabsetPanel(
        tabPanel("SubPanelB1"), tabPanel("SubPanelB2")
      )),
      tabPanel("Tab3", tabsetPanel(
        tabPanel("SubPanelC1"), tabPanel("SubPanelC2")
      ))
    ))