Updating choices using updateSelect(ize)Input causes selection to be cleared

[jcheng5]

With selectizeInput(multiple = TRUE), calling updateSelectizeInput(session, "id", choices = ...) causes the selection to reset, even if the currently selected item is in the set of choices. (Doesn't happen without multiple = TRUE.)

Same with selectInput/updateSelectInput, with both selectize=TRUE and FALSE.

System details

shinylive

Example application or steps to reproduce the problem

https://shinylive.io/r/editor/#code=NobwRAdghgtgpmAXGKAHVA6ASmANGAYwHsIAXOMpMAGwEsAjAJykYE8AKAZwAtaJWAlAB0IdJiw71OY4RBEBiAAQAZWp1KKiAM0UATKK06adpbnEUB3OHADWI-YYD62x1duKAPAFpFBdkLAAWRIHANxFAIAVAFc4TlC8CLAAdThdCDiE8KjuaMZ4gzCkgDFGWiykgGUoUjyKgMroiATZEWjaTx9UKABzOEctanbdfwhFXxYRkXHxzjhqOAJSWgAvOABJCFRo0n8wB0c5haWihvnFjSg9QsSCbiJaAjjFAF5rpxc3G3Cji7TXpLBZo3cIwaLUZaoBYAyJYACqAFEBLhpjMoEtaCQAEI7UgkPbRVD6ciOeikOSJAJwok1cwAYXujziAWRqPG5AAHqQAPI7ba7AK-JZpRwtVGyVoQOaMABucEYnUUWiaGPxfH54SIfJ2PzinExEAEihAqK1pH5ABIheRdKKDIrGBRdPLInAuewTWMZt11HA9gBNLWKa1pRBFdU7C0Ha2ycYAX1jES9RCk8rlCLlZHYEdIFsJxP6ZIg4U9M0U+dplXOGLWm35XD1Buy+wMh2rpCKdweTyMbwcnGcWlc1m+wfb-zefgEiYTIjjIhEPD4rAAguh2O1dbL5bIwHGALpAA

Click the button, see that the selection is reset.

[jcheng5]

Same with py-shiny.

https://shinylive.io/py/editor/#code=NobwRAdghgtgpmAXGKAHVA6VBPMAaMAYwHsIAXOcpMAMwCdiYACAZwAsBLCbJjmVYnTJMAgujxMArhwl1KAEzh1ZcKITIcAbnAA6EPQGImAGQ4thxGk3lRsLJpaZk2cJgHc4cANZ6bdgPqW-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-pAA

[gadenbuie]

Here's a modified version of the example app that shows the behavior of selectizeInput() with both multiple = TRUE and multiple = FALSE in the same app.

Example app

library(shiny)
library(bslib)

# List of days of the week
days_of_week <- c("Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday")

ui <- page_fluid(
  card(
    layout_columns(
      selectizeInput("day_select_mult", "Select a day", choices = days_of_week[1:5], selected = "Monday", multiple = TRUE),
      selectInput("day_select_single", "Select a day", choices = days_of_week[1:5], selected = "Monday", multiple = FALSE)
    ),
    input_switch("include_weekends", "Include Weekends"),
    textOutput("selected_day")
  )
)

server <- function(input, output, session) {
  output$selected_day <- renderText({
    paste("You selected:", paste(input$day_select, collapse = ", "))
  })
  
  observeEvent(input$include_weekends, {
    new_choices <- if (input$include_weekends) days_of_week else days_of_week[1:5]
    
    updateSelectizeInput(
      session,
      "day_select_mult",
      choices = new_choices
      # selected = intersect(input$day_select, new_choices)
    )

    updateSelectizeInput(
      session,
      "day_select_single",
      choices = new_choices
    )
  }, ignoreInit = TRUE)
}

shinyApp(ui, server)

[gadenbuie]

This bug has been around for a bit, I can reproduce with at least Shiny 1.7.0 (Sept 2021). (Note it might go further back, I just picked a sufficiently old version to make sure this isn't related to work I did earlier this year.)

[nirguk]

In my experience the following idiom on the R side is quite common

  observeEvent(input$update_btn, {
    sel <- c()
    prev_sel <- intersect(input$day_select,days_of_week)
    if(isTruthy(prev_sel)){sel <- prev_sel}
    updateSelectizeInput(session, 
                               "day_select", 
                               choices = days_of_week, 
                               selected = sel)
  })
}

perhaps it points the way to a solution ?