uiOutput

Question

所以我一直在努力处理这一行代码。我的uiOutput函数似乎杀死了它下面的所有内容。
运行文档时，我的 uiOutput（“ SELECT_STAGE_1”）
下没有任何内容 但是，当我删除此行时，其余代码将被呈现，而当我放回该行时，我的 uiOutput（“ SELECT_STAGE_1”）出现，但此后没有其他显示。
我在设置的“ renderUI” 行上做错了什么吗？

    ---
    title: "ALICE"
    output: 
      flexdashboard::flex_dashboard:
        orientation: columns
        vertical_layout: fill
    runtime: shiny 

    ---
    ```{r setup, include=FALSE}
    library(flexdashboard)
    library(tidyverse)
    library(leaflet)

    STAGES <- read_csv2("20191122_STAGES.csv")
    STATIONS <- read_csv2("20191122_STATIONS.csv")
    TRAJETS <- read_csv2("20191122_TRAJETS.csv")

    output$SELECT_STAGE_1 <- renderUI({
      liste_stage_1 <- STAGES$ETABLISSEMENT[STAGES$DEPT == input$DEPT_1]
      selectInput("SELECT_STAGE_1",
                  label = NULL,
                  choices = liste_stage_1,
                  selected = NULL)
    })



    Column {data-width=1000}
    Hello
    selectInput("DEPT_1", 
                label = NULL,
                choices = sort(unique(STAGES$DEPT)),
                selected = "AUCUN")

    uiOutput("SELECT_STAGE_1")

    sliderInput("WANTED_TIME", "Wanted time", 5, 90, 10)

    checkboxInput("UNAUTRE", label = "I need a second entry", value = FALSE)

    conditionalPanel(
      condition = "input.UNAUTRE == true",
      selectInput("DEPT_2", 
                  label = NULL,
                  choices = sort(unique(STAGES$DEPT)),
                  selected = "AUCUN"))

感谢您的帮助！