关于R Shiny/R Studio的一般问题...
我注意到，当我运行R Shiny应用程序时，到目前为止，我编写的所有程序都按预期运行。但是，如果我在后台打开窗口，并切换到使用其他程序，（例如Excel，Chrome等），或者有时候即使我在窗口上，几分钟后窗口就自动关闭了。然而R Studio显示它仍然在监听，并且在我按下STOP按钮终止应用程序的现有运行之前，它不会运行进一步的代码。
在开发应用时，这种行为在R Studio中是正常的吗？还是表明我的代码有问题，导致它消失了？当它消失时，控制台中没有出现警告消息。我尝试使用我找到的一些基本示例代码运行另一个应用，也发生了同样的事情。
如果这是一件平常的事情，为什么它会这样做，有没有办法阻止这种情况？
示例代码可能不相关，但这里有一个来自RStudio网站https://shiny.rstudio.com/articles/basics.html的示例应用程序。这个应用程序也会出现这个问题。

ui <- fluidPage(
  
  # App title ----
  titlePanel("Reactivity"),
  
  # Sidebar layout with input and output definitions ----
  sidebarLayout(
    
    # Sidebar panel for inputs ----
    sidebarPanel(
      
      # Input: Text for providing a caption ----
      # Note: Changes made to the caption in the textInput control
      # are updated in the output area immediately as you type
      textInput(inputId = "caption",
                label = "Caption:",
                value = "Data Summary"),
      
      # Input: Selector for choosing dataset ----
      selectInput(inputId = "dataset",
                  label = "Choose a dataset:",
                  choices = c("rock", "pressure", "cars")),
      
      # Input: Numeric entry for number of obs to view ----
      numericInput(inputId = "obs",
                   label = "Number of observations to view:",
                   value = 10)
      
    ),
    
    # Main panel for displaying outputs ----
    mainPanel(
      
      # Output: Formatted text for caption ----
      h3(textOutput("caption", container = span)),
      
      # Output: Verbatim text for data summary ----
      verbatimTextOutput("summary"),
      
      # Output: HTML table with requested number of observations ----
      tableOutput("view")
      
    )
  )
)

# Define server logic to summarize and view selected dataset ----
server <- function(input, output) {
  
  # Return the requested dataset ----
  # By declaring datasetInput as a reactive expression we ensure
  # that:
  #
  # 1. It is only called when the inputs it depends on changes
  # 2. The computation and result are shared by all the callers,
  #    i.e. it only executes a single time
  datasetInput <- reactive({
    switch(input$dataset,
           "rock" = rock,
           "pressure" = pressure,
           "cars" = cars)
  })
  
  # Create caption ----
  # The output$caption is computed based on a reactive expression
  # that returns input$caption. When the user changes the
  # "caption" field:
  #
  # 1. This function is automatically called to recompute the output
  # 2. New caption is pushed back to the browser for re-display
  #
  # Note that because the data-oriented reactive expressions
  # below don't depend on input$caption, those expressions are
  # NOT called when input$caption changes
  output$caption <- renderText({
    input$caption
  })
  
  # Generate a summary of the dataset ----
  # The output$summary depends on the datasetInput reactive
  # expression, so will be re-executed whenever datasetInput is
  # invalidated, i.e. whenever the input$dataset changes
  output$summary <- renderPrint({
    dataset <- datasetInput()
    summary(dataset)
  })
  
  # Show the first "n" observations ----
  # The output$view depends on both the databaseInput reactive
  # expression and input$obs, so it will be re-executed whenever
  # input$dataset or input$obs is changed
  output$view <- renderTable({
    head(datasetInput(), n = input$obs)
  })
  
  
}
shinyApp(ui, server)