multiple choice box in R/shiny - adding a scroll bar

I build an R/shiny web app. I want to have a multiple choice box (I use checkboxGroupInput(), but am open to alternatives). However, the list of choices is long and I want to contain it in a relatively small box of options (that shows 5-6 options at a time) with a scroll bar that enables to scroll through the entire list of choices. Is there a way this can be done? minimal example: ui.R ``` library(shiny) choices = paste("A",1:30,sep="_") shinyUI(pageWithSidebar( # Application title headerPanel("my title"), sidebarPanel( checkboxGroupInput("inp", "choose any of the following", choices) ), mainPanel( tableOutput("result") ) )) ``` server.R ``` library(shiny) shinyServer(function(input, output) { myInput <- reactive({ input$inp }) output$result <- renderTable({ x = myInput() if(length(x)==0) { x = "No Choice Made" } matrix(x,ncol=1) }) }) ```