Select multiple choices in selectInput() when selectize=F - r

Question

How can I select multiple items in selectInput() when selectize=F?
library(shiny)
library(shinydashboard)
shinyApp(
ui = dashboardPage(
header = dashboardHeader(),
sidebar = dashboardSidebar(),
body = dashboardBody(
uiOutput("box1")
),
title = "DashboardPage"
),
server = function(input, output) {
output$box1<-renderUI({
box(
selectInput(inputId = "in", label = "Choose", choices = c('Short','A very short sentence.'),
selectize = F,multiple=T, size = 5, width = "150px")
)
})
}
)

Answer 1

What you have is allowing multiple selections.
You may see it more clearly if you add this (even if it's temporary)
Add verbatimTextOutput(outputId = "res") after the uiOutput("box1") (don't forget to add a comma) and add output$res <- renderPrint({input$`in`}) after output$box1 in server
library(shiny)
library(shinydashboard)
shinyApp(
ui = dashboardPage(
header = dashboardHeader(),
sidebar = dashboardSidebar(),
body = dashboardBody(
uiOutput("box1"), # comma added here
verbatimTextOutput(outputId = "res") # this is added
),
title = "DashboardPage"
),
server = function(input, output) {
output$box1 <- renderUI({
box(
selectInput(inputId = "in", label = "Choose", choices = c('Short','A very short sentence.'),
selectize = F,multiple=T, size = 5, width = "150px")
)# ends the box
}) # ends output$box1
output$res <- renderPrint({input$`in`}) # this is added here - since 'in' is a keyword I would suggest a different id...
} # ends server call
) # ends shinyApp