sidebarPanel(
   selectInput(
      "plotType", "Plot Type",
      c(Scatter = "scatter",
        Histogram = "hist")),
   # Only show this panel if the plot type is a histogram
   conditionalPanel(
      condition = "input.plotType == 'hist'",
      selectInput(
         "breaks", "Breaks",
         c("Sturges",
           "Scott",
           "Freedman-Diaconis",
           "[Custom]" = "custom")),
      # Only show this panel if Custom is selected
      conditionalPanel(
         condition = "input.breaks == 'custom'",
         sliderInput("breakCount", "Break Count", min=1, max=1000, value=10)
      )
   )
)Run the code above in your browser using DataLab