Delay in tabPanel content update when Sidebar control is updated - r

Question

In the Shiny app below I am updating tabPanel content when the selection in sidebarMenu changes. However, there is a minor delay in the tabPanel content update when I change the selection in sidebarMenu.
For the small number of input values, this delay is negligible, but when I have a selectizeInput control in sidebarMenu and I load 1000 values there, then the content update in tabPanel is substantial. Is there a way to update tabPanel content instantly? Something like - content in all tabs is updated as soon as someone makes a selection in sidebarMenu, even before someone clicks at the tab?
library(shiny)
library(shinydashboard)
siderbar <- dashboardSidebar(
sidebarMenu(
# Add buttons to choose the way you want to select your data
radioButtons("select_by", "Select by:",
c("Food Type" = "Food",
"Gym Type" = "Gym",
"TV show" = "TV"))
)
)
body <- dashboardBody(
fluidRow(
tabBox(
side = "right",
selected = "Tab3",
tabPanel("Tab1", "Tab content 1", textOutput("tabset1Selected")),
tabPanel("Tab2", "Tab content 2", textOutput("tabset2Selected")),
tabPanel("Tab3", "Tab content 3", textOutput("tabset3Selected"))
)
),
)
shinyApp(
ui = dashboardPage(
dashboardHeader(title = "tabBoxes"),
siderbar,
body
),
server = function(input, output) {
# The currently selected tab from the first box
output$tabset1Selected <- output$tabset2Selected <- output$tabset3Selected <- renderText({
input$select_by
})
}
)

Answer 1

Using the outputOptions to set suspendWhenHidden = FALSE updates the outputs also if they aren't visible:
library(shiny)
library(shinydashboard)
siderbar <- dashboardSidebar(
sidebarMenu(
# Add buttons to choose the way you want to select your data
selectizeInput(inputId = "select_by", label = "Select by:",
choices= as.character(1:1000))
)
)
body <- dashboardBody(
fluidRow(
tabBox(
side = "right",
selected = "Tab3",
tabPanel("Tab1", "Tab content 1", textOutput("tabset1Selected")),
tabPanel("Tab2", "Tab content 2", textOutput("tabset2Selected")),
tabPanel("Tab3", "Tab content 3", textOutput("tabset3Selected"))
)
),
)
shinyApp(
ui = dashboardPage(
dashboardHeader(title = "tabBoxes"),
siderbar,
body
),
server = function(input, output) {
# The currently selected tab from the first box
output$tabset1Selected <- output$tabset2Selected <- output$tabset3Selected <- renderText({
input$select_by
})
lapply(list("tabset1Selected", "tabset2Selected", "tabset3Selected"), outputOptions, x = output, suspendWhenHidden = FALSE)
}
)
Furthermore you should consider using a server-side selectizeInput to enhance the performance for many choices.