R Shiny如何给模态对话框添加滚动功能避免shinyMatrix矩阵压缩

运行如下MWE代码时，如底部图片所示，用户在模态对话框渲染的矩阵中进行输入会导致矩阵被压缩。用户输入的矩阵列数越多，压缩程度越高，最终矩阵会难以阅读。

是否可以在新增列时不让矩阵压缩，而是向右延伸，由用户通过滚动条进行左右导航？我今日尝试插入滚动条但尚未成功。

该问题可能源于shinyMatrix包本身。考虑到DT Table展示效果好且自带滚动功能，能否将shinyMatrix作为输入输出的后端引擎，前端改用DT Table实现？rhandsontable包虽然界面美观，但在模态对话框中运行效果不佳。

library(shiny)
library(shinyMatrix)

ui <- fluidPage(

  sidebarLayout(
    sidebarPanel(
      uiOutput("panel"),
      actionButton("show2nd","Show 2nd input (in modal)")
    ),
    mainPanel(plotOutput("plot1"))
  )
)

server <- function(input, output, session){
 
  output$panel <- renderUI({
    tagList(
      matrixInput("input1", 
        value = matrix(c(10,5), 1, 2, dimnames = list(c("1st input"),c("X|Y",""))),
        rows =  list(extend = FALSE, names = TRUE),
        cols =  list(extend = FALSE, 
                     delta = 1,
                     delete = FALSE,
                     names = TRUE, 
                     editableNames = FALSE,
                     multiheader=TRUE),
        class = "numeric"),
      helpText("Generate curves (X|Y):"),
    )
  })

  observeEvent(input$show2nd,{
    showModal(
      modalDialog(
        matrixInput("input2", 
          value = if(isTruthy(input$input2)){input$input2} else
                  {matrix(c(input$input1[1,1],input$input1[1,2]), 1, 2, 
                          dimnames = list(c("2nd input"),c("X|Y","")))},
          rows =  list(extend = FALSE, names = TRUE),
          cols =  list(extend = TRUE, 
                       delta = 2,
                       delete = TRUE,
                       names = TRUE, 
                       editableNames = FALSE,
                       multiheader=TRUE
                       ),
          class = "numeric"),
    footer = modalButton("Close")
    ))
  })
  
  observe({
    req(input$input2)
    mm <- input$input2
    colnames(mm) <- trunc(1:ncol(mm)/2)+1 
    isolate(updateMatrixInput(session, "input2", mm))
  })
  
  output$plot1 <-renderPlot({
    req(input$input1)
    plot(rep(if(isTruthy(input$input2)){input$input2[1,2]} else 
            {input$input1[1,2]}, times=10),ylab = "y")
  })
  
}

shinyApp(ui, server)

矩阵压缩效果 #

模态输入框滚动效果参考 #

内容的提问来源于stack exchange，提问作者Curious Jorge - user9788072