spsComps gallery only enlarges once - r

Question

I got an app that opens up a modalDialog with an image inside a spsComps::gallery. However, the enlargement works only the first time the modal has been opened. How can this be fixed? Here is a minimal reprex:
library(shiny)
library(spsComps)
ui <- fluidPage(
actionButton("modal", "Open modal")
)
server <- function(input, output, session) {
observeEvent(input$modal,
{
showModal(modalDialog(
title = "test",
fluidRow(gallery(
texts = "Click to enlarge", hrefs = "", image_frame_size = 6,
images = "https://cdn.pixabay.com/photo/2018/07/31/22/08/lion-3576045__340.jpg",
enlarge = TRUE, title = "When you close this modal, the enlargement does not work again",
enlarge_method = "modal"
)),
footer = modalButton("Cerrar"),
easyClose = TRUE,
size = "xl"))
})
}
shinyApp(ui, server)
The first time the modal is opened, you can enlarge the image by clicking it. It looks like this:
However, when you close and then reopen the modal, that enlargement feature is missing.

Answer 1

A temporary fix would be this:
library(shiny)
library(spsComps)
ui <- fluidPage(
actionButton("modal", "Open modal"),
singleton(
div(id = "sps-gallery-modal", class = "gallery-modal",
style="display: none;",
onclick = "galModalClose()", tags$span(class = "gallery-modal-close", "X"),
tags$img(id = "sps-gallery-modal-content",
class = "gallery-modal-content"),
div(class = "gallery-caption")
))
)
server <- function(input, output, session) {
observeEvent(input$modal,
{
showModal(modalDialog(
title = "test",
fluidRow(gallery(
texts = "", hrefs = "", image_frame_size = 6,
images = "https://cdn.pixabay.com/photo/2018/07/31/22/08/lion-3576045__340.jpg",
enlarge = TRUE, title = "When you close this modal, the enlargement does not work again",
enlarge_method = "modal"
)),
footer = modalButton("Cerrar"),
easyClose = TRUE,
size = "xl"))
})
}
shinyApp(ui, server)
The reason is I have this singleton(... in the gallery creation function. There is only one enlarge img container needed to be created no matter how many galleries you have (It's not practical to enlarge two pictures at the same time). So enlarged images from different galleries are displayed inside the same enlarge container. This saves computer resources, and singleton in Shiny is the function to prevent duplication. Even if you may call gallery many times, if the content inside singleton is sent to the DOM tree only once, it will not append it again.
The problem is when showModal is closed, Shiny deletes everything inside the modal, including the gallery singleton content. Meanwhile, I think the singleton content validation stays at R level. It does not actually go search the DOM tree if this content exists or not. So Shiny thinks singleton content is there, and therefore refused to send it to DOM when the second time you call showModal.
The fix above append singleton content to fluidPage container instead of Shiny modal container, so when modal is closed, it cannot delete the content.
This is a universal problem in Shiny when you have singleton and modalDialog. There is nothing I can do to fix Shiny, but I may think of a more user-friendly way in the next spsComps version to address it.